Mailman 3 is acceptable, imho. It's been a few years since I worked with it, but I was able to design a reliable public instance of it (https://mailman.haskell.org) with a few days of effort, including the migration from mailman v2.

Mailman 3 is horrible, which is why some folks have ported Mailman 2 to Python3.

https://github.com/jaredmauch/mailman2-python3

Lol this makes sense. I really respect the author of mailman3's dedication, but the architecture of the system is insane. There are 3 services -- the actual mail delivery piece, the admin interface, and the archiver -- all talking over various public and local interface, configuration is a nightmare, logs are all over the place, it takes over your system with scheduled cron jobs, there's some kind of built in console that I can't figure out how to use due to virtualenv issues plus cli commands that cover only some of the necessary functionality. It's gotten better since I run the tool as two docker containers, but still ends up being the most difficult service to administer and I administer quite a few

Same here — I think I set Mailman 3 up in a day, although I was already familiar with setting up the mail (Postfix) part.

I’ve heard good things about <https://mailinabox.email>.

Besides GNU Mailman, there’s also Sympa [0]. It’s fairly straightforward to set those up on a VPS with Debian or similar if you’re familiar with running a Linux server.

[0] https://www.sympa.community/

Same for self-hosted mail...

I haven't tried it, so it might be more complicated than the documentation leads me to believe, but Mox looks promising: https://www.xmox.nl/

I've been using it for a year now. Can vouch for the quality and reliability

I use Postfix and Dovecot. Configuration was annoying, but doable. If you read mail on the server itself then you don't need Dovecot.

Proxmox has a mail appliance.