Tom bought a few domain names and has used them to create email addresses for all his kids. He's been able to forward the MX records to Gmail, but he's having issues being able to associate the domains with the actual accounts. Leo suspects that Google may be restricting it for those who pay for Google workspace. They're not going to allow it for free accounts because there's no benefit to Google to do so.
Leo recommends Fastmail. It's a paid service, but it supports it more affordably. Can he transfer them to Google Domains and go that way? Leo says sure. He can do that. That will give a better chance. Another option would be to change the DNS settings!