I have a pixel 6a and it works great. However, I did run GrapheneOS shortly after I got it, so that may be why. I don’t use the Stock OS.
So google might be trying to get you to buy the newest phone? I know apple likes to slow down their old phones so people upgrade, maybe Google does the same.
That’s actually a surprise to me, seeing how they wouldn’t let people sideload. Can’t believe the app store would allow pirates.