Earlier quoted context omitted.
I agree with hitekker, I'm feeling pretty nervous about being a FastMail customer right now and will start looking for a more secure alternative now. The main reason I moved to FastMail is because I stopped trusting Google to keep my mail secure.
Google is the gold standard for email account service. Nobody in the industry does a better job at that one thing than Google does.
But I've started to think about moving back to Chrome for "high security mail".
My private mail is pretty bland and uninteresting, so I don't care too much about not using GMail there, but for my Apple account, Google account, Microsoft account etc. it might be a good idea to compartmentalize those "high value" things from everyday mail and go to GMail with the Advanced Protection Program (so no access from smartphone or iPad, I guess).
And looking at their web site I've learned that GSuite Business is affordable and allows adding domains hosted elsewhere. Good.
What do people think about this?
But then the next step: what about losing my domain? My registrar is a reputable German domain hoster, but certainly no Google. On the other hand, Google doesn't register domains, but has "domain partners" like "domaindiscount24" (that I've never heard of before), so I guess not much to win there.