It is possible I am not understanding your comment, but Addy.io does not hide your emails from Google, no? It just forwards them from an alis to a mailbox, but they are normally not encrypted themselves
If you use some ADDITIONAL third party client to cypher the mails, basically if you cannot read them on gmail.com, then that should be ok hehe
But then again, why not switch to Proton/tuta?
Oh I see, that's nice then! Only thing that might help, maybe switch from GMail to Proton as the inbox? Although they have a more limited space...