It's really just postfix + rspamd.

rspamd is very, very impressive. I guess most of the hard work I've put into it is adding some of the not-turned-on-by-default things, like Pyzor and Razor. Also adding some other RBLs that weren't included by default (I spent a lot of time personally researching them and only picking ones that I believed to be of high value) The other big thing that I think is important is the RBL whitelists - DNSWL.org and HostKarma have a whitelist as well.

About one a week I spend 10-15 minutes looking at the logs of what it's accepted/rejected during the week to see if I can spot any obvious mistakes - it's pretty rare. If I do spot something I make config changes to address it. That said there's been months before where I haven't done this and none of the users of my platform have complained about spam (or missing email)

rspamd really is that amazing. I don't understand why more people don't scream it's praises from the rooftops.

I think that's pretty standard for everybody who runs its own mail server (like "shared webhosting"-running even). Owning your mail should also be standard for everybody in tech, you don't want to rely on Google for something that important.

Exactly. I rely on Google for a number of things, the primary thing being photos. But I've read too many horror stories (on here) of people losing their Google account and thus their life. So all my photos are also backed up locally and then into a BackBlaze bucket.

Using Postfix+Rspamd gave me good insight into SPF, DKIM and DMARC and how to use them effectively.

I mean, electricity is also very important, but that doesn't imply that everybody in tech should be configuring their own wiring. It's fine to do that if you want to, but it is completely reasonable to expect that most people should be able to rely on someone else to do the work of ensuring that the key infrastructure runs well, and not think about it so that they can focus on the specialization they want to handle.

We're not talking about running bare metal in your garage but paying Hetzner or alike 2,50 Euro/month so you're independent from the shenanigans of the automated, AI-"improved" systems of Google. That's a fair price to pay if you value your electronic communication abilites.

I suspect it’s not that unusual. In six years of running my personal mail server, I’ve received exactly zero spam messages with grey-listing as my sole anti-spam measure. The only time I got spam was when I had to move my domain to a new server and forgot to enable the postgrey service.