dark horizontal bar across top of screen

I’ve been experiencing a black bar across the top inch of my screen. When I take a screenshot of the full screen, I can’t see any of the problems in the picture, so it seems to be a display issue. I’ve tried doing a NVRAM reset, but that hasn’t really helped. What does seem to work temporarily is closing my Macbook lid for long periods of time, and also shutting it down every night. When I reopen the computer, it looks normal for maybe 20 minutes, but then the flickering starts.

This goes on for a little while, with the lines getting darker and darker. (Note: the yellow box is just an edit to the image.)

Eventually, the top of the screen is just covered in a thick black bar. My cursor does not show up in that area. It’s like it just disappears behind the darkness. Here is a picture. (Note: I’ve shrunk down my windows so the tabs are visible below the black bar, and the yellow are just edits to the image.)

There’s also a problem with faint traces getting left behind when I switch windows. I’m not really sure how to describe this better, but for example, I’ll minimize my Chrome browser, and behind it, I’ll have my Spotify app open. Some leftover images from the Chrome tabs will be visible on the Spotify app.

Other weird stuff that happens:

The problem is just restricted to that strip at the top of the screen. Any ideas on how to deal with it?