I replied to this post yesterday, then realized maybe the solution is to use an email worker? There is a template for dropping emails for a specified list of senders I was going to try to look into reading headers and see if SPF status is in there and create a rule around that. Before going down that path thought to inquire here and see is anyone else has tried setting up a worder for this purpose, or could confirm if SPF and/or DMARC status are in message headers.