How can I improve my performance?

I get the same issue (pie menu lag on the fridge, computer) and I have a pretty good PC. I think the sims development team is going to have to do something on their end to improve the performance of pie menus under the hood, since it seems like the more options and interactions they add, the worse it gets.

The modder Lumpinou has a good post about it here:
https://www.patreon.com/posts/misc-about-pie-2-121299166

For frame stuttering, I don't know, since I don't experience that unless there's some aurora happening in the sky or the eco footprint thing. Are you playing on Laptop mode with lower settings and v-sync enabled?