I've recently switched my personal email to a brand new domain and am struggling with getting it delivered. And all I'm doing is ~100 emails a week hand written by me to other individuals. I've been doing Internet email for 35 years now, I used to handwrite sendmail.cf for my college. I'm worried the medium is going to fail entirely in 5-10 years because of complexity in spam fighting.

Receiving mail: I was using Google Workspace to accept email to my domain and then forward it to my personal @gmail.com address. And Gmail was blocking emails forwarded from Google Workspace. Not because the original email was suspect, no, but because Google Workspace isn't forwarding email correctly (ARC or SRS related) and so the SPF check failed. The solution for that was to use Cloudflare to forward my incoming email instead. They are doing ARC right, or in some other ways the signatures arrive intact so Gmail sees valid SPF instead of invalid. Now my mail gets delivered reliably.

Sending mail: I only ever send mail to Gmail. I have DKIM set up and just set up a strict p=reject policy with DMARC. This seems to be working pretty well. I did have to add Cloudlflare as another authorized DKIM source so the mail forward works, but that's OK too.

Basically we've shifted the trust problem from "does this email look legit" to "do I trust the companies that are sending this email?" This all works only if Gmail and Cloudflare don't screw up and allow spam. (Which is already failing: I get a lot of Gmail spam.) So email is now consolidating into the hands of a few companies. It is not working well as a peer to peer Internet medium anymore.