[speedyapoc]

With the way Google and other providers have shutdown accounts with impunity, it’s hard to think of anything but a custom domain being a safe option.

[IgorPartola]

You can move a custom domain easily enough. I am about to do that to move away for the GSuite’s fees. Worst case, I’ll invest into running a service on my own. Best case, I’ll just use Proton or FastMail, etc.

I guess registrars can go down too but it seems less likely.