AFAIK, I can purge Googleware from my phone with Shizuku and replace it with microG, but I'm afraid it is unsafe

Don't quote me on this since I haven't done it, but IIRC that's something that you can only do during a fresh install

i actually don't even use microg, there's no problem at all. you don't get push messages, and some apps might not run tho i havent encountered any yet. (i don't run banking, drm, anything like that)

Yeah. I've been using it for years.

GrapheneOS prefers using sandboxed Google Play instead for security and functionality reasons, but they are pretty obscure. In theory, microG could be used to install a malicious app with elevated permissions, since it has the ability to bypass security checks. If you trust the apps you install, then it's a non-issue. It's potentially less functional as an open-source implementation, since it is not a perfect 1 to 1 replacement of Google services. You may find that there are certain functions it just can't do. I don't know of any specific examples.

I don't think you can do that. But if you can, go ahead, it's not unsafe in the sense that your phone will catch fire or anything.

But you should always have backups of anything you can't afford to lose.

If you can root the phone, you can do it after an install. Did it on a OnePlus that didn't have a LineageOS image at the time. It worked fine, all apps stopped complaining about Play Services being off.

I had only one app that used some obscure map API that would work only with Google Play, and crashed with MicroG. All while even Google's own Maps worked OK.

Yeah go for it

The only app I've ever had trouble with on Graphene with no GS in main profile is the myq garage door app oddly.

Everything else has been fine

If I need something that requires play services I can run it in the private space

I wish Graphene was my case but my phone is unrootable. My best is just deleting googleware via shizuku and installing microG instead. That's what I think is dangerous: not microG, but installing it like this

My comment was not specific to GrapheneOS. Although I do use it and trust them when it comes to security assessments. It's not perfect functionality, but it should provide most of the basic functions. I would have to imagine if you're using Shizuku that it can install it with the proper permissions. Someone mentioned checking the XDA forums, which is probably a good idea before you make any serious changes.

That garage door app and every app that conglomerate foists upon its users is a poorly-coded huge POS made more for their ability to show you ads than anything else

Absolutely. It was bought and installed by the previous owner. It drives me absolutely insane that this is the one app that decides to reject Graphene when everything else including banking and travel apps are running fine. MyQ blames it on CloudFlare