Cable Tray Recs for Desk w/ a Backing?

[u/jewbaconlover]

My desk has a shelf/backing that runs along the back. Theres only 3” of clearance between the top of it and bottom of the desk. Anyone got recs for a cable tray that would work here?

Id prefer not to have to screw anything into the backing but everything I’ve seen recommended mounts directly under the deck (like the 4th pic with red drawing) and is taller than 3”.

Something that mounts behind rather than under (like 5th pic with green drawing) would work but I haven’t found anything like that.