Usually when people have speed problems with Jetbrains IDEs it's one of two things:
1. Heap size is too small and it's GCing a lot without the user realizing. Open IDE VM options and double the -Xmx setting.
2. Using a 4k display on macOS. Try the new JBR17+Metal builds. They aren't shipped yet but switch it to using Metal to render. Makes it a lot faster.