Is that really a relevent attack vector in your day to day use, that full disk encryption wouldn’t cover? My browser is rarely closed when I am on the PC, so it would be accessible (because unlocked).

Stalwart is 95% awesome. What holds me back is, that Mails are stored in a Database and not Maildir. Maildir is insanely trivial to backup incrementally and to restore individual mails if necessary. That currently holds me on dovecot.