If you’re just using it to read, I would highly recommend selling it and getting an e-ink display. I have both a Kindle Paperwhite and Kindle fire 8 plus. I just can’t read books on the fire 8 anymore, the Paperwhite is so good. If you can’t stand Amazon then rakuten makes a really good e-ink readers with their kobos.
That’s odd, I installed the Gemini app on my 6a like a week ago. Unless you’re specifically talking about grapheneOS.