How do I get this overlay away (see picture)?

On my laptop, this overlay has recently appeared when I want to write uppercase or lowercase letters and, to be honest, it gets a little upset…

Does anyone know anything about this and could tell me how I can turn it off?

I also had a problem, so I just pressed the capital letter again. Then this ABC was crossed out for about 3 minutes, then it was already gone.

If I press it for a long time, it goes away, but if I press it again, it comes back. Do you think that will go away on its own after a while?