The closest thing we have to this is probably protondb but I’ve never seen any super in-depth tweaks from users there. I’m also not 100% sure if they have non steam games posted there. If they do I imagine there’s not exactly a ton of posted guides by users

Oh my bad. According to another commenter it is sandboxed though

They have Google services but through a third party wrapper called MicroG, which keeps it sandboxed to a degree that you can keep it from doing system-level actions like this

edit: not microG, as evidenced by the strikethrough I put in very soon after receiving the first of several replies clarifying the situation. I would encourage you to read one of them before adding your own. <3