Personally I'd be tempted to switch to Discourse, which has an email
participation mode if desired, and has SaaS options if you didn't
want to self-host. It's what I'd have replaced BitFolk's mailing
lists with if there weren't so much pushback from people who are
wedded to the 20th century mailing list experience.
I think I might have advocated in the past for the 20th century mailing
list experience. I do like email, but it does seem you have good
reasons for moving away from email. Like it or not, it does seem to
become a technology that is slowly but steadily being made incompatible
for anyone but google and microsoft.
Thus, for my part, if it makes your life easier, I'm sure I could learn
to live with discourse if that's what you want to do.
Conrad