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.
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.
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.