What are some ideas to help make my gameplay better?

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?