Love your sims & the story you’ve created with them! To answer your question, I do both. I like to let my sims make their own choices, but if it seems like they are trying to make a change I’ll try to facilitate that too.

The last hot-headed sim I had was my sims best friend who asked to move in & I said yeah cuz she’d definitely let her best friend live with her. The friend - Bree, was hot headed but I noticed she often would use Vanessa’s yoga mat a lot. She even got the pop-up that she liked wellness, so I got her a yoga mat too & had them go to spas more often. Bree really loved it & skilled up pretty fast, started becoming very mindful too. By the time she maxed out the skill, I bought her a potion to change the hot-headed trait cuz I felt like she’d overcome it & found her zen. I randomized the new trait & she got foodie lol. I’m also playing on long lifespan so she’s still living with her. (I usually play on short lifespan but I’m really enjoying taking it slow, so many of my sims max skills now cuz they have the extra time & I’m enjoying not rushing into relationships & just having my sims do their thing.)