I run various Gmail accounts through the Apple Mail client so I set up rules and filters on the Gmail server side. I also do the same on iCloud my personal account. This way all of my rules migrate over to all of my devices. This works well for me.
I use iCloud mail and set up my rules on the server side so mail gets processed and sorted before viewing on any of my devices. Harder to set up since I have to use the iCloud web interface to configure the rules and can’t do it from Safari on iOS.
I just saw today that I can now mark an item as read AND send it a folder, i.e. most often the Trash…
This was not possible before in iCloud.com but thankfully it is now. Also the loft for how many rules one can have on iOS is gone. I think it has been for a while, but I just noticed that today also, running amok with setting up “mark-as-read-and-send-to-folder-creation”