No bootable device message. Can't do anything.

On my mac mini late 2012 running macos Catalina, I downloaded windows 11 iso for boot camp, because it said it could run windows 10 or later and once it finished, it automatically booted into it, but the windows 11 installation said my mac couldnt run it, so i exitted it and turned off the mac. Now whenever I turn it on, it shows a black screen, my keyboard flashes off and on after like 30 seconds a random part of the screen flickers and says "No bootable device -- insert boot disk and press any key" Any keyboard combination results in the same thing. I've tried putting both windows 10 installation media and windows 11 installation media in a USB and into it but it still shows it. Also I'm using a windows kind of keyboard, not an apple one, so there's a windows key and an alt key.