I recently moved my family's legacy GSuite service over to Fastmail, and it seems like they've carefully planned for this exact scenario. Account setup on each device is as simple as downloading a configuration profile with a QR code. And Fastmail has a built-in option to authenticate to your old Google account and pull all your mail over to the new account, preserving all the details, and then keep sync'ing until you're ready to turn the old account off. I thought I was going to have to sync things myself. Nope! Took all of five minutes to set up my account and sync. Couple weeks later I deactivated the old GSuite accounts.
And now I'm a customer again, which feels good, even though it means spending actual money.
I recently moved my family's legacy GSuite service over to Fastmail, and it seems like they've carefully planned for this exact scenario. Account setup on each device is as simple as downloading a configuration profile with a QR code. And Fastmail has a built-in option to authenticate to your old Google account and pull all your mail over to the new account, preserving all the details, and then keep sync'ing until you're ready to turn the old account off. I thought I was going to have to sync things myself. Nope! Took all of five minutes to set up my account and sync. Couple weeks later I deactivated the old GSuite accounts.
And now I'm a customer again, which feels good, even though it means spending actual money.