In addition to my answer to your original request, I can inform about stuff related to WhatsApp.
You can use WhatsApp on a Matrix server with a bridge. You can either selfhost or find a server which has the WhatsApp bridge.
There is also Beeper - now acquired by Automattic (WordPress, …) - which is a company matrix server with many bridges (they employed the person developing most of them). You can use a FOSS matrix client like Element X or their own client which is not FOSS but requires far fewer permissions than the WhatsApp app
I don’t think you can install it outside of GrapheneOS though
Corporate app frontends track everything you do and see. They can record your mouse movement and watch it again, they track your scrolls, every button click, and even sometimes what you type in inputs even when you don’t actually save them (like an Instagram comment you decide not to post, or a video search you don’t actually search). There is a lot of tracking done on the frontend. Some of it could also be done in the backend (and a part of that is), some not
What’s the point with what I said? The official repo has apps that are not signed by the developer but by this third party (repo mainteners)