I've been self-hosting an ancient mailman 2.x service for many years for the residents' association where I live, and it's time to move on.  Apart from anything else, I dread to think what security holes may still exist.  But we're experiencing issues with SPF failures causing bounces and eventual unsubscribes, which I'm not even sure mailman 3.x handles any better than 2.x.

So I'm looking for recommendations on a way forward, and figured this list is full of knowledgeable sorts who probably have experience with various options.  I should mention that these lists are used for discussion, not just for broadcasting one-way announcements.

mailman 3.x seems to be substantially more complex than 2.x, but I don't see that as an issue, because I've decided to move away from self-hosting since I just don't have time to become a mailman expert.  Moving to SaaS would also increase the service's bus factor above 1, and provide some added security through isolation from other services currently on the same machine.

I'm loathe to move to Google Groups since some of our residents are very anti-Google, and I expect their support will be awful if ever needed.  It's also a closed source dead end.  I'd prefer to pick a SaaS offering based on Free/Open Source, to support continued development of that.  I'm inclined to go with a mailman 3 SaaS offering, and the following two both look very promising because they're decently priced, can migrate my existing 2.x lists, and can host on London servers:

https://www.mailmanhost.com/ 

There's also https://mailman3.com/ which can host in the EU, but I'm not sure if they offer migration.

Does anyone have any experience with any of these, or have recommendations of good alternatives to mailman (preferably with options to migrate existing mailman lists)?

Thanks a lot!

Adam