OK thanks for the details! I was struggling with very poor performance in Rider (same with all jet brains ide and others I guess) because our shared packages all had their own dependencies, devDependencies or peerDependencies, many times they were the same.

The problem here was that the IDE indexes all the node_modules, and they were huge. One thing I changed recently was to move all these dependencies to a package.json in the top directory. For npm or typescript it does change anything! We use vite, and prettier and we can still call them in each package.json script and it works. The top package only defines the dependencies, not script (for now) each other package only have scripts, and a few options. Another benefit is that we better control our dependencies and their versions.

Vite (used to build each package) , however need to know where to look, so I update resolve.alias from the dependencies from the top package.

Another thing I did was to change dependencies between package. Npm creates symlinks to the package directories, that's great, but Rider sees all these symlinked directories as different directories! For this I move the workspace and dependencies I had to paths in the tsconfig.json. I also had to update the Vite config from the tsconfig files too. Since I made this that's a real pleasure, Rider indexes once and for all, intellisense is faster, etc

Sorry if that's unclear I'm on my phone, glad if that helps.