Recovering Notes linked to inaccessible Gmail account on iPhone

I’m having trouble accessing my Notes on my iPhone. They just dissapeared this morning.A long time ago, my Apple ID was linked to an old Gmail address that I no longer have access to. I can’t sign out or turn Notes back on.

I tried recovering that Gmail account, but Google says that the account does not exist. When I try to create a new Gmail with the same name, it says the username is already taken — so the account exists, but I cannot access it at all or maybe it's deactivated.Because of this, I cannot turn Notes back on, and I’m afraid of losing them. Please help me recover my Notes.

[Re-Titled by Moderator]

Original Title: I'm having trouble with Notes and my old gmail connected to my apple id