Hmm yeah, I thought this is about organisation internal discussion. Of course if it is just a mailbox for outsiders to use, you could just configure some forwarders so that multiple people get the emails and can respond from their own account if necessary.
Selfhosting email specifically is quite hard. Not so much technically, but because of how a few large providers have cornered the market and drop most self-hosted emails reaching them with the excuse of fighting spam.
Hosting a forum that requires login credentials (incl. 2fa etc.) is quite easy though. But I guess that wouldn’t work as a way for outsiders to contact you.
And a future you might decide differently.