i run several mailing lists for my community. it's a pain. of all my self-hosted projects, mailman 3 gives me the most ongoing trouble. it's a very complicated piece of software and it's running in an increasingly hostile internet. i literally just spent an entire day finally setting up ARC and learning arcane things about how DMARC and SPF validation will still fail when you've ARC-signed your mailing list messages, but it's okay because lots of providers (really, gmail) will give you "points" for the ARC signing, but also you still should enable conditional DMARC mitigations in case the sending domain has a very restrictive DMARC policy, at which point mailman 3 will munge your From headers making list replies get all janky and confusing for all your non-technical participants.

i don't want to be on a mailing list for a bunch of random unrelated people who don't know each other and have no reason to be civil to each other. mailing lists for shared projects make sense, and mailing lists for people who otherwise are somehow engaged in community. a mailing list for random people sharing cool ideas honestly sounds it will either totally die, or will first become really controversial and THEN totally die. even in my social circle, some of the mailing lists i ran were torn apart by politics and people splintered off to start their own mailing lists without the people with "problematic" opinions, only to learn that the "problematic" opinions were what fueled the whole shebang.