This may be a rather silly question, but still I'd be glad if anyone could enlighten me a bit here.
I have installed GrapheneOS on a Pixel4a, but not the Sandboxed Google Playservices and I would prefer not to install it, even if it is sandboxed. So far only one app seems to be making trouble, and I can probably find an alternative, but the app gives an error message, when I open it, but when I click ok, the warning disappears and the app seems to work perfectly, so in this case it seems that the app functions fine without, but just makes a check for Playservices and then gives a warning. Therefore I'm kind of wondering what Google PS actually does? In this case it seems to just work like the Fakestore, that many rooted phones use to spoof Google PS.
If I install Sandboxed Google PS, does it change anything on the phone? Obviously the above app works fine without it, so if I install Google PS will it supersede any existing functionality on the phone for example notifications?
If I install it, I would like it to do as little as possible and not interfere with the other parts of the OS at all.