Another way to check whether it is a fake/broken keyboard problem can be use a "key logger" application. A few (many) years ago I made an application that caught all keys pressed. It was an application to program a programmable keyboard. All pressed keys (with the exception of Ctrl+Alt+Del) were redirected to the application to allow programming of any key. The application was of course reported by security application as keylogger. A Windows keyboard hook was used to remove the pressed key from processing and storing it in the sequence for programming. It was (I think) in the time of Windows XP and it requested to allow the hook. (Needed for this purpose.) I do not know whether it will work on Windows 10 (with the hook). Application[^], product support page[^] Another way is to use Workrave[^] -> System tray: right click -> Statistics -> Activity. This will report only key presses.

I have the same problem on my old PC. I can have three working monitors (HW devices), but only two screens in Windows (without the use of USB to monitor, docking...) All three monitors can be active only in the case when two monitors display the same screen (screen duplication). It is a limitation of the graphics card HW. The PC (motherboard) support up to 2560x1440 resolution only on DP and maximal 1920x1200 on HDMI/DVI/D-Sub. But with the use of docking station (USB3 --> DP) I was able to connect even 4K monitor. Therefore it is clearly (in my case) a HW (motherboard) limitation.