Bottom jockey wheel on rear derailleur keeps skipping chain
From the the photo of the derailleur it's obvious that the derailleur cage is not parallel to the sprockets and wheel. The bottom run of the chain returning to the crank is leaving the cage at angle.

The derailleur hanger that attaches the derailleur to the frame is bent and causing the misalignment, and I think the cage may be deformed as well.

There are special tools for realigning the derailleur that a bike shop can use, but it's possible to improve it by hand. From the back of the bike look down the chain. The cage should look parallel to the chainrings. You can grab the derailleur and bend it back into alignment.