What are some ideas to help make my gameplay better?

Maybe you should give us some ideas of what you would be interested in. There are so many different types of players that it can be hard to give out one size fits all advice.

As the above said it really depends on what it is that you want out of the Sims 4, and that's super different between players.
That said, I may as well go on a usual Snowbnuuy ramble, and give you a general bit of advice from me on what helped me improve my own experience:

If you are possibly finding the game too easy, or you are looking for more 'direction' in your gameplay, then have a look at doing one of these challenges. They can make the game more challenging or give you more of a goal for you to work towards; when I got bored with freeplay, challenges got me back into TS4. If not challenges, give yourself 'house rules' for specific saves or households. Lot Traits also help with adding another layer of relative difficulty to the game. Maybe you could have an off-the-grid house or a haunted house if you have Paranormal Stuff. There's a lot of little mix-and-match ways you can make the game a bit more of a challenge.

I understand your own gameplay experience you're looking for may be different than mine, in which case ignore me, but I just wanted to share anyway. Unfortunately as someone who doesn't use mods, I can't suggest any that might streamline the game or add stuff to the game that might suit you. Either way I hope you find some ways to make things more fun for you ~

@Calico45 and @GlacierSnow I feel like my gameplay is not interesting to me anymore. I have mods like the "slice of life" mod and "wonderful whims" mod. I love the sims and I doubt that I will ever be truly tired of it but I used to look forward to it every day and now not so much. As @SnowBnuuy mentioned I think it has become too easy for me.

Hmm... I'm not much of a play-for-the-challenge person. In fact I typically use mods to get rid of challenge and make things easier. My focus is always more on playing out a story that I'm making up in my head, so the built-in gameplay challenges often get in the way of what I want to create, and I have more fun if I remove them so that I can freely do what I want from my own imagination.

But if you prefer things to be more difficult, I think @SnowBnuuy 's suggestions to take a look at some of the player challenges is good. Adding some rules and objectives could be fun for you. By putting limits on what you can and can't do, you can create some more difficult scenarios that you might get excited about.

Most of the things in game that I can think of which can be challenging are things like having a household with a lot of toddlers, having several sims in the university at the same time, giving your sim an aspiration that is counter to their traits (like a gloomy comedian for example), or using some of the lot traits like "off the grid", "cursed", or "gremlins". I don't have Paranormal yet, but it sounds like the haunted residence can actually be pretty challenging too if that interests you.

And, nothing wrong with pursuing other interests for a while. Sometimes boredom is just a sign that you've been doing one activity too long, and it's time to do something else until you feel drawn back to the original thing you loved.

Everyone is different on this and there isn't a one size fits all answer. Some people do play with challenges as others mentioned and that might be a fit. In my case, I'd either say to make a sim or group of sims that you really like and want to play. Not sure which one to pick? You could make a group of them and then pick your favorite. I've done that for sims when I didn't know who should be the spouse. In one case, I sent him to Selvadorada with three different women and he really hit it off with one.

Another thing you could do is to pick a few townies and edit them until you like them whatever that means. "This one is nice and funny. That one is a little clumsy but I want to know what happens next." If there's something you like about the sim, it can be a lot of fun.

While I've sometimes sent myself back to houses that I didn't want to replay at first because it fit with my overall game, most of the time, I think, "What do I want to do?" So, that can be the same thing for you. If you just want to build, you can. If you want to try a challenge, you can. If you want to come up with a story, you can. Pick a different house in a world that you haven't played.

Sometimes, I just play likeable sims and they have fun in different ways. Since I switch between them, I experience different things. Recently, I made a specific townie playable because she seemed interesting to me. You could do the opposite and play with a bunch of characters that you dislike to do whatever deviant playstyle you want.

I like having different types of challenges but the main thing is not to force yourself into what you don't want to do, just do whatever you want.

I could give you specifics but I think it's important to start from that point, what do you actually want to do? I've taken various breaks as well and change things up whenever I want. Concentrating on what you find to be fun is probably the most important thing. If that's boring to other players, so what?

Do you play rotationally? I saw this suggested a bunch on YouTube, and it really got me rengaged. Having a bigger cast of sims allowed me to play out more focused stories at the same time. It’s also fun to see how all my different sims interact with each other, and who is interested in who, what the next generation will do, etc.

Another thing you could try is looking for a save file that someone has shared and play in that. I downloaded one a while back that had a ton of new families and new lots (the Bee Save, I think it was called). The key thing that made it interesting for me was the interconnectivity of the different packs; I’m not a builder, so I was using existing maxis builds and dumping random community lots into Newcrest. This save had spas in the resort areas, themed restaurants in various worlds, nightclubs where there had been penthouses, and so on. It inspired me to put together my own save; the lots are from various builders who are redoing each word, so each lot has a place to go in each word. I downloaded a bunch of decent looking townies to fill it out. Each time I’ve moved my favorite sims between the saves, so it’s not totally starting over but each save feels more alive to me.

When mine became a little boring I added this weird two game load where load 1 is entry into load 2

So load 1 is where my sims have to earn a spot in load 2 which is the main save load.

All load 1 play is challenge play. Be it a sim does rags to riches (or rags to can afford to buy a home in load 2) or surviving the bachelor to become a couple or whatever challenge I give them I get to "know" them so my load 2 or main load is always fun to play in rotation. I love seeing my sims "make it" to load 2 but not all do. Some sims are truly duds.

It's made for a true cast of characters in my main save because it's like I'm building their character arc and only the sims I truly enjoy make it to the main load.

I never have perfect sims. I always add "negative" traits. I love having conflicting characters together such as a gloomy and cheerful sim. A slob and squeamish sim. I just try to make it ironic and fun with a little mischief. A cop and a criminal marriage. I don't have a lot of cheerful, outgoing, good sims. They're lucky to get one of those traits.
We, my husband and I play together, find it fun to pair opposites.

The rotational play keeps it fresh for me in the main load and the "survival of the fittest" challenge load offers another game play style in the challenges load. It's nice and mixed up for me and solved, at least for me, the boredom I had.

It would also be useful to know what kind of gameplay experience you currently are having, or that you have had in the past, and why you are no longer satisfied with that. Otherwise we might just tell you things you've already tried and rejected.

I see. The obvious is like @SnowBnuuy mentioned, challenges. If it is too easy, set up some obstacles yourself. Since you are open to mods, there are probably a number of them that will expand the difficulty in veins you are interested in.

I, personally, do not care for challenges. It isn't about the difficulty so much as the inspiration for me, and when I do not have it I can stop playing for large spans of time. The thing that jogs it the most? Real life/time and new content. If nothing is coming to you naturally in life, I'd advise looking to expand your pack selection or mod catalogue. There is a chance even just browsing could inspire you.

In the challenge vein... Well, getting a whole household through Uni is brutal. I've done it with seven controlled Sims. I was genuinely too busy to pause sometimes. I also really enjoy haunted houses and off the grid lots, and full households. I have every pack and no mods (tried, seemed like too much upkeep) so I usually just throw it all at the wall when I play.

Worst case scenario, a break isn't the worst thing. It can refresh you for the next time you play. I play other games when the Sims 4 doesn't hold me. If you don't, maybe you could play an older version of the Sims. I currently have 1, 3, and 4 all on the same laptop.

You could try living as homeless person, I am kind of doing that now and enjoying it so far. You'll still have lot expenses but they're marginal, if you have outdoor retreat you can use tent to sleep in at public lots like park once you afford it, place it's shower anywhere if you need a shower, mega cooler you can grab free quick meals and water/juice from and can use park grill to make other food. Not exactly on same level as having house in terms of food options, you can use the park toilets and sinks for last needs outside socials.

While it isn't like super challenging it does give like a different style playthrough, if you kind of forbid yourself from going to your lot. Instead rely completely on all other lots that are public access.