-
I was thinking about this last night..
How did you do the migration? Just import everything into fastmail from gmail and then forward gmail to fastmail, gradually changing incoming stuff over to fastmail? Did you send out a big notice to everyone saying to email you on fastmail instead of gmail? Did you not enable forwarding and just run two mailboxes side by side until gmail stopped getting stuff?
Presumably you still have your gmail account(s) to access Drive or Sheets or whatever stuff on your phone or did you kill all that off too and use other apps?
I started that process a few years ago but it's too much of a headache and I stayed on gmail, etc.