I still handle email for multiple small businesses (for over 20 years) and recently switched from the mailscanner+spamassasin to rspamd and the scanning is so much better/easier now

my backend is still dovecot+postfix, still works beautifully. I am able to run rspamd+dovecot proxy on a small vps and the storage is handled by a backend office server with dovecot. If VPS has an issue can spinup another easily/anywhere and backend is also virtualized (libvirt) so easily restored (with multiple backups in multiple places)

biggest thing to worry about with deliverability is ensuring your SPF and DKIM (opendkim) are correct, which is not too difficult and rspamd is able to handle the dkim signing/verification which is nice