Chromium doesn’t need Chrome to exist either: it’s a separate project and if Google doesn’t want to support it anymore, someone can easily fork it to continue having Chromium-based browsers. That’s the property of open source: anybody can inspect and fork it.
When I was talking about “battery charging”, I meant using an app to limit the charging at a certain level: look for “acca” or simple “acc” which is the module/daemon to manage that. You have to be root to do that and there is no way around. For the rest, sure, but that’s for GrapheneOS, I was talking in general, most ROM not having what GrapheneOS has and considering GrapheneOS is exclusively present on Pixel phones unfortunately…