I read all the praise about Claude Code, tried it for a month and was very disappointed. For me it doesn't work any better than Cursor's sidebar and has worse UX on top. I wonder if I am doing something wrong because it just makes lots of stupid mistakes when coding for me, in two different code bases.

I'll suggest giving it another shot. It really is a game changer (I can't tell what you're doing wrong, but in a few people I've seen it has been about doing a psychological switch. I wrote about it a bit here - https://mnvr.in/beginners-mind, sharing in case it helps you see how you might approach it differently)