Feel free to join us during contributor meeting or on our dev chat on matrix.
We can discuss about this things, but as Aleks explained we have not a lot of knowledge on rspamd.
Maybe some topics on this forum could be helpfull to (don鈥檛 know i didn鈥檛 read it 
Comment am茅liorer la d茅tection des spams (configuration rspam)?
Questions sur rspamd
Rspamd, filter and mail
And on issue Tracker:
[rspamd + clamav] add antivirus in the core! 路 Issue #1459 路 YunoHost/issues 路 GitHub
[dovecot] spam mailbox is not created 路 Issue #1456 路 YunoHost/issues 路 GitHub