I recently switched launchers. Have you tried Kvaesitso? It’s the best I’ve tried. It allows you to create categories in your app drawer, and organize that way. I’ve really been liking it.

https://github.com/MM2-0/Kvaesitso

I’m not sure I understand what you’re asking. It seems like you’re asking why your clangd extension isn’t working? But then you say:

BTW I’m not talking about using clangd with the vscode flatpak package

If you’re on Linux chances are using a package manager. Do you think the package maintainers won’t compile the features(well maybe, Debian)? It still makes no sense as most users would have the feature anyway.