Definitely NOT video games. If OP wants to replace staring at phone it needs to be something that will not constantly reward him.

Games, phones, social media are extremely addictive as they give us constant rewards. Reading an actual book becomes boring. I suffered from the same problem with games. I had to uninstall games and completely stop playing for a week or two before I had an itch to do something else like reading a book or studying. It is insanely scary, and for me it was bad. Even to a point that I would say that it is an addiction.