I think this is kind of unimportant, if you want to improve your experience developing frontends, establish a design system in close collaboration with the desi

I think this is kind of unimportant, if you want to improve your experience developing frontends, establish a design system in close collaboration with the designers (use something like atomic design for example) and build abstractions that implement the design system around a component-based architecture. I feel like that's much more important to think about than whatever particular CSS framework you use. Also think about how you are going to optimize for LCP/FID/CLS (core web vitals), its gonna be hard optimizing that later.