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.

Material Files and Amaze

Aurora still works for me for now on Samsung stock OS. I now mostly install Google Play apps with APKPure over Obtainium tho and only use Aurora for those not on APKPure. And most of my apps are from GitHub/GitLab releases and F-Droid. I disabled Google Play and didn’t login to Google account. I don’t want the requirement of a Google account to install an app and Play Integrity to run an app. It is by no means acceptable that a company, using a closed source implementation that also tracks user and breaks Android security model, can censor what apps a user can install and decide what security and privacy compromises a user needs to agree to just use the normal phone functionalities that they pay for and by no mean require those compromises technically. They are turning Android into a service and a prison like iOS did rather than a software.

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.