Fatih Camera is a big part of my life and its really important for me to keep Google Camera app. is this possible with Graphene OS? will it function the same and receive updates?
Yes, GCam works fine (although I have not tested it)
Fatih so we get monthly android updates?
Yes.
Fatih can we install Graphene OS on At$t locked pixels? does it affect anything?
Not sure specifically, but any kind of locked pixel won't let you install GrapheneOS. The phone has to be Carrier Unlocked and OEM Unlockable.
Fatih are all apps still downloadable and installable? like even APKs Im good with that
Yes. You can download apps from Google Play (if you install GPlay Services), F Droid, Aurora Store, Accrescent, and GitHub APKs.
Fatih any concerns with Graphene OS as a main daily driver OS?
Nope, its great! I love it.
Fatih Any problems with background app usage or background photos upload on Proton Drive? or any other service?
I don't have any problems. All background usage works as it should and Proton Drive uploads photos fine.
Fatih Can I still access google apps fully functional if I want?
Yes. Google Play Services are not installed by default, but you can install them and use all Google Services. But Google Pay will NOT work. Keep this in mind if you use it. Even with GPlay Services, GPay doesn't work.
Fatih Do banking apps and authentication apps (MS or Google authenticators) work fine?
No problems with authenticators but banking apps can be a problem. Some work, some don't. I'd recommend you check the list for your bank to see if its compatible.
https://privsec.dev/banking
Fatih Do we still have the same customization options for the Ul (lock screen widgets, apps shapes and colors,...) that regular pixel users have?
There is customisability. Lock screen widgets, app shapes and colors included.
Fatih Do we have clipboard in the keyboard if its not Gboard?
I haven't tried with the stock keyboard but I'd imagine it does. I use HeliBoard, which is really great and has an integrated clipboard.