I am looking to self host emails for a small non profit organization. MX plans are cheap when buying a domain name but come with poor webmail like Roundcube[0] which really feels outdated when compared with Gmail or Fastmail. I am looking to self host a full featured modern webmail client but can’t find any. Why ?
Soho[1] is the best I have found and supported by Gandi[2].
This doesn't really answer your question about why there aren't many options, but: did you find mailpile[1] on your travels? It could be worth considering too.
Why not use something like Postfix or Exim with a local application like Thunderbird?
Also unless this is a tech-savvy organization or emailing or FOSS is part of their mission, consider just sticking with something from Google, Microsoft or Fastmail. A shelter for homeless kittens probably doesn't want to mess with something custom.
It's not as easy as you imagine, especially when you want to make it "simple" like Gmail, there's a lot of work that goes into a "simple for the user" interface.
