[1] - https://support.mozilla.org/en-US/kb/openpgp-thunderbird-how...

Yes. My outgoing email goes out via Sonic's SMTP server, with the SPF records to allow it to have a source address of my own domain. Incoming email goes to my own domains and gets forwarded.

This seems to be trouble-free. The domain is on a cheap shared hosting account. I'm not running a server. I own the domain, and not though the hosting company, so I can switch to another provider if necessary. In 27 years, I've had to do that twice, because the hosting provider went out of business.

This is easy to do, and I don't have to deal with Google. I don't even get much spam. All the spammers seem to be targeting the big services now.

I just looked at my spam folder. I'm regularly being offered dental supplies, large hydraulic sheet metal bending presses, and ammonium sulfate fertilizer. It seems that having your own domain now means you get mostly business-to-business spam. I subscribe to Machine Design, which gets me some heavy industrial marketing, but I have no idea why I get dental supply ads. The fertilizer spams, from China, look like a scam - there's a fertilizer shortage, so that's a spam which might get replies.

You can also even keep Gmail as your MX server! Just move messages off of it as soon as they arrive. It's just a mailbox, after all

Third party email providers, the so-called "established businesses", get a free pass as sending SMTP servers that are accepted by almost all receiving STMP servers. Everyone just assumes everything coming from those SMTPs is legit. Establishing this "legitimacy" and getting the "free pass" is difficult and some have suggested, the third parties may employ anticompetive tactics.

However, IMHO the receiving SMTPs is a different issue. Why do we let these third parties receive and store our email. (Why do our homes have their own mailboxes. Why not use a "P.O. Boxes" instead.) Eventually we could move away from letting third parties control the receipt of our mail. Neither "POP3" nor "webmail" was part of the original concept of email.

Today, it is easier than ever to set up overlay networks where we can assign our own IP addresses and run our own SMTP servers that can communicate directly with other SMTP servers on the overlay network. These networks are not open to the world, they may only be open to people we know. Much of our mail is between people who know each other, e.g., friends, family, colleagues. Or businesses that we contact first. We can separate different social and business networks on different overlay networks.

Anyway, the sending and receiving of mail can be separated. We do not need to let a third party control both.