Note that the GrapheneOS developer has indicated they are working on getting the Google Play Services apps to run sandboxed like normal apps, without extensive system permissions. This could be quite promising.
Some non-Twitter prose about the Play Services support (though it doesn't include the tweeted info about dynamite support being nearly finished): https://grapheneos.org/usage#sandboxed-play-services
Upgrading to a new-to-you few-hundred dollars Pixel every 2-4 few years isn't anywhere close to the expense of a new $600-$900 phone every 1-3yrs, the way people used to (and the way iPhone users still seem to).