Hmm I'm confused. I have my own domain that is totally not hosted on google. However, I use Google's SMTP to send mail as that domain (specifically the one email address that is enabled on my custom domain).

For that I'm authenticating to the SMTP with my google account, and I somehow proved to google i own the email a couple billion years ago when we all had pet dinosaurs.

Are they discontinuing that or something else?

And Q2: if this is what they're discontinuing, are there any other email solutions that would support something like this? I.e. incoming email to my server I control 100% but offering smtp relay?