Black box, middle-top of the screen. What is this, what app is responsible for it, and how do I kill it?

The phone is an INOI A54 on Android 13, stock ROM, rooted with a recovery Magisk patch. There is this black bar in the middle of the screen, at the top, that appeared when I got a call. *A black rectangle in the middle of the screen at the top with a phone icon inside of it* After the call ended, the bar stayed and could not be removed. Upon clicking on it, it launches the dialer app via some "DIAL" intent/action. This bar is really annoying, and I would like to know what setting or app causes it to appear. What I've tried already: 1) Looking through basically all notification settings 2) Uninstalling the dialer app 3) Changing dialer apps 4) Killing any processes I could find that are remotely related to the calling activity 5) Checked the accessibility settings, nothing useful there, too. 6) Also tried to search for "overlay" and "quick access" in the search bar, nope. And I still could not fix it. The only "solution" is to reboot, but I'd have to do it every time someone calls me. I think that something that can be tried is checking the UI layers in some kind of debugger and then searching by package. That would solve it, I think, but I don't know any. So, what I'm asking is: 1) If this bar can be disabled by changing some setting, then what is it, and where do I find it? 2) If it can't, then what app/process causes it? So that I can kill/restart/disable it.