+1 for the ability to add additional rspamd plugins
I had not heard of Irondome, with DA I was using Spamhaus DQS with Rspamd and had almost 0 spam that came through apart from ones sent from hotmail/gmail etc for Website development, SEO services etc but these had been set to block through the leaning.
Link for the install guidehttps://github.com/spamhaus/rspamd-dqs
Scans IP Data [SBL/XBL/PBL + AuthBL], and Content Data [DBL + ZRD], Hash Blocklist also available