No, in my experience, selectodude is right. I've written this rant before but I think it's worth sharing repeatedly, so here goes again:

The big players (Google, in particular...in case it's not clear, the bulk of this rant is leveled at Google; Microsoft is an offender on perhaps 25% of the level, Yahoo just doesn't seem to care) have ZERO interest in "playing nice" with small e-mail servers. My experience running my own e-mail for almost twenty years then finally throwing in the towel and migrating to Fastmail not only proves this for me, but is, according to other sysadmins I've talked to, quite common.

I did everything right when hosting my e-mail. I did it for myself and maybe four others. The volume of mail going out of my server was so low, I could read the outbound mail.log for myself, and routinely did. Every domain had SPF, DKIM, and DMARC records. The outgoing single IPv4 and IPv6 addresses I used had perfectly-matching forward and reverse DNS lookups. I had a script that checked every blacklist I could find every 24 hours. My IP addresses were allocated from my (professional) colocation provider and SWIP'd to me with valid contact information. My IP addresses had been unchanged for seven years and had been stable for ten years prior to that change. My colo provider had a draconian non-spam policy. Nobody ran an e-mail list or anything. I've used the exact same domain for e-mail for over twenty years.

Still, every couple of months, Google (sometimes Microsoft, but far and away most likely Google) would decide to simply stop delivering messages from my five users--remember, including me--to Google's users. The messages would just...disappear. Sometimes, Google would stop delivering the messages mid-conversation. Replies would be going back and forth but then my reply to a Gmail user would go to /dev/null while their messages to me would still arrive. Most of the time, the mail would go to spam (even with that little yellow tag meaning "verified sender" or some such) but 20% of the time the mails would just disappear.

Worse, the destination would say "250 OK" to every e-mail I sent them so I had no way of knowing that the messages had been sent to the big bitbucket in the sky. I got annoyed.

I signed up for Google's Postmaster Tools and Microsoft's similar offering. Microsoft would at least show me telemetry but it wouldn't do any good. Google? Google would proclaim that I wasn't sending them enough e-mail so I couldn't show up on the dashboard.

Finally, after three years of fighting this, it came to a head when I was, at all places, at a boardgame meetup during one of these "blackout periods" and got introduced to a Google SRE who worked "adjacent" to Gmail. "Oh, hey, you should talk to techsupporter, he does e-mail too!" was the opening line. We talked, I ranted, and he actually said he'd try to help. He escalated internally and the word came down from on high on their SMTP team or some such: "domain [mydomain] has insufficient reputation."

What did that mean? Apparently, their system--at least at that moment--thought my domain was "too new" and they tilted towards just binning the e-mail. I got red, saw stars, then gave Fastmail $390 for three years of service on three e-mail accounts and moved everything to them within five hours. That was the last straw, the final injustice. For me, the "decentralized Internet" died on that day.

Why was I so pissed? Observe these dates from WHOIS:

Domain Name: MYDOMAIN.ORG
[...]
Creation Date: 1997-03-10T05:00:00Z

Domain Name: GOOGLE.COM
[....]
Creation Date: 1997-09-15T04:00:00Z