The first suggestion I'll offer as a mail list alternative (with operation via the web an option) is https://groups.io
I am a subscriber to one group of lists that offer software support for a package I used to use, so it has similar benefits for those that need to offer multiple mail lists for slightly different audiences.
I also subscribe to another private, invitation only, list.
Light traffic lists are free and without adverts.
Both of those I subscriber to moved there from YahooGroups when they closed down. For those with long memories. I understand that the guy who started it created OneList a decade or two ago. He sold out to eGroups and they sold to YahooGroups, so the thing has gone full circle.
However, I have no experience as an list administrator.