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              Custom ROMs have had just about enough of being Android's second-class citizens
 
            
            (www.androidauthority.com)
          
          This is a most excellent place for technology news and articles.
GrapheneOS, and other non-OEM OSes, do not. It's kinda the whole point of the article/OP I linked.
Have you tried playintegrity fix?
Nope, nor do I intend to. GrapheneOS frowns upon rooting and modifying the system as it typically widens your attack surface. I'm not using a secure OS then going around to purposefully make it less secure.