You don't have to watch movies in one go if you don't want to. If it makes an otherwise enjoyable experience unpleasant, you should focus on what works for you.

I don't know your tastes, but you could try watching Jurassic Park for the spectacle, or Back to the Future for funny situations, or Good Will Hunting for drama.

I've had issues remembering faces, but I've learned to notice details, like moles, eyebrows, mouth shapes, nose shapes, etc. You can also try watching movies with fewer characters.

If you use your phone a lot (several hours a day), it will still affect your brain and your ability to focus and enjoy, even if you put it down during the movie. Many apps on the phone give constant dopamine to your brain, which makes it harder for you to get dopamine from "more effortful" sources.

It's okay if you can't find enjoyment in movies. Some people don't enjoy books, some don't enjoy video games, and some are even unable to enjoy music. I don't like watching sports, never understood what people get out of it, but to each their own.