Yikes! good luck, hope it works out. This is scary. Gmail is still, by far, the best email app. Something like this could happen to me and, I suspect, a lot of other people.
I used to think so when I used Gmail.
But switching to Fastmail, I no longer agree that it is "by far" the best. Now I think Gmail is only better by a slight margin, and this margin is so small that it does not justify the drawbacks: Potentially getting locked out with no recourse, certainly getting everything you receive scanned to deliver you the best possible ads, contribute to the email monopoly where the big players decide the protocols.
I find this opinion absurd. It is an e-mail client. Even if it did perform the tasks that an e-mail client needs to perform somewhat better than all other clients, the loss of autonomy makes it a terrible deal, even for non-technical users.
True, no mails no problems, it's a feature not a bug.