A lot of people get very into creating backstories for premades thrn aging that premade down, creating (or aging down ) friends and family then playing it out in game.
I did it with Johnny Zest and played him in the homeless teen mode until he earned and bought his trailer. Then i played him through get famous up to a 5 star celeb.
Other people have played Caleb and Lilith before they became vampires and the story of their turning. Or aged down Vlad.
The pack sims both old and new have interesting backstories to expand upon.
I can also recommend challenges especially those that have specific goals for each generation and force you to try new aspects of the game you may have ignored e.g. try out the criminal career or be a style influencer. Not so berry and the drifter challenge both do this with new goals for each generation. The drifter challenge has build goals as well if live mode is not for you at present.
I also played a family on short lifespan and the rush to achieve things left no time for boredom (but I get too attached and losing them too quickly meant I couldn't do this for an extended time).
Finally I watch a lot of YouTubers to get inspired. Laurenzside and call me kevin are definetely simmers who push the boundaries of what you can do with sims and don't play normal games. Englishsimmer has good plot driven let's plays for inspiration. And kevin sauce has a great series.
Good luck.