I think limiting from the platform is not a good option. For some teens with a horrible family (domestic violence for example), social media maybe the only shelter they could turn to. Also, those companies tend to break open web and require an account and even verification in the name of protecting child. DNS blacklist enforced by parents is probably a better option IMO.
Also ban Google. I think we should ban any schoolwork in required courses that requires students to agree to any third-party EULAs, such as Google account and Windows OS. For selective courses, considering the de facto status that many fields don’t have a mature enough open source software, banning is a bit exceeding proportionality IMHO. And offering Windows computer is probably ok as long as it’s not the default choice IMHO.
In my freshman year in the Electrical Engineering department, I took a required computer programming course, the course that I supposed it to be most aware of the existence of GNU/Linux, free format, and so on. However, it uses Google Sheets for homeworks and demands a Google Drive link of an exe for final team project and YouTube link for presentation. When they let students evaluate each other, I just got a bunch of exe, half of which doesn’t even open in Wine.
I also think they every school should offer NextCloud. Otherwise when team work occurs, Google Drive/Docs/Slides/Sheets is the de facto only choice.
BTW, I think LaTeX with git is more customizable and extensible and should be taught instead of teaching MS Office stuff. I actually take all my notes in LaTeX in a GitHub repo and do reproducible compilations.
If you mean those ro.product.*, ro.system.*, ro.vendor.*, etc. and some other device identifiers, I think you can adjust many of them when compiling GrapheneOS yourself, which, however, requires a lot of storage and computational resources. If you mean the user agent HTTP header (and navigator object), there’s no such thing as a system wise UA since UA is to recognize the OS and browser combination, and the UA header can be spoofed with those user agent switcher extensions or, if you are advanced user and want fine control, Header Editor, which can be added to Android Firefox by visiting it with desktop enabled.