ps. I suspect that this will provide people a very simple way to migrate to using free Gmail as their email solution. (though in my case, I've taken the free Gsuite product closure as an incentive to fully de-Google).
Does Cloudflare have any options for handling outgoing email? If not, I assume you still have to set up your actual email host in a way that can send through all the vanity domains, with appropriate DKIM records, etc.
Actually, I was wrong: it looks like there's no longer an option to do that from Gmail :(