I see this advice (that you should use a custom domain) and it makes me a bit hesitant in that I’m not sure I necessarily trust a registrar more than I trust Go

I see this advice (that you should use a custom domain) and it makes me a bit hesitant in that I’m not sure I necessarily trust a registrar more than I trust Google not to allow phishing/hijack/deletion. That said there’s really two issues if you seperate out the inbox - access to new emails, and access to the historical emails you’ve accumulated. The second can be partially helped by downloading all mail + attachments from the server and keeping a backup. The first is more complicated either way you look at it.