What are some ideas to help make my gameplay better?

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.