When using #m2sync, compared to #mbsync, you need to use "maildirpp:" instead of maildir "maildir:".
Just though to mention since I was puzzling around this for few hours, and wondering why #notmuch finds everything, and aerc finds nothing.
EDIT: Had some issues with this but it seems interesting and relevant so I keep tracking this project. Now I at least got the mbsync bug fixed in Fedora.
#m2sync
I found a modern actively updated alternative for #isync (or #mbsync): #m2sync
It is part of #vomit project: https://sr.ht/~bitfehler/vomit/
Compared to the complexity of ~/.mbsyncrc, my config is now dead simple:
cat .config/vomit/config.toml
[kapsi]
local = "~/.cache/mail/kapsi"
remote = "mail.kapsi.fi:993"
user = "jjs"
pass-cmd = "pass show imap/mail.kapsi.fi"
I love vomit!
Client Info
Server: https://mastodon.social
Version: 2025.04
Repository: https://github.com/cyevgeniy/lmst