trying to make positive changes in a Sims life, and it only makes me feel worse about trying to improve my own situation.

Haha same, whenever I was working on improving their life, I was always acutely aware that I could be spending that time improving my own :D I guess there was some satisfaction from wish fulfilment (they own a house, wow), but yea I always spent an afternoon setting up mods, another day or 2 playing, then just got bored. Rinse and repeat every couple years. (Though I haven’t touched Sims 3 since the pandemic, and never tried Sims 4 so whatevs xd)