My main suggestion here is just that an established reputation for a specific IP/domain should override the reputation of the IP block it's inside of.
Thanks for clarifying, ok, hmm… that seems hard to do if you can check the IP block by using a subnet mask but the specific IP isn’t resolved until later in mailflow. It might not actually work like that in… ProtocolFilterHub? I always get this mixed up, wait… I think this might be something that we are already working on. And have been working on for a while, wow. Looks hairy. It’s stuck since the guy working on it transferred to another team, and no one picked it up, but some PM noticed before I did and put it up for vote in semester planning. Always creepy to see engineers get referred to as “resources”.