Migrating anonymous account

So it seems like an anonymous account is unrecoverable, but can be updated into a linked and recoverable account. I can't figure out how to stop it being anonymous though. sometimes logging into the game I have the option of a game save tied to my Google account from a long time ago that I can't delete, or the anonymous one I've been playing for years. If i could remove the game save associated with my Google account would that mean I can upgrade from anonymous to cloud saved and onto my new phone? I've been looking for a way to do this but I cannot find it