It's still not displaying 😅 do you know what else I could do?
Maybe it's something else more simple. Where is the display cable connected to? Did you move it to troubleshoot? If processor isn't an apu model with integrated graphics the motherboard video ports won't work and need to connect cable directly to graphics card.
Enter Bios, chapter 3.2 of manual.
Soon as pc is turned on, in POST phase, mash delete or F2 key. If keyboard has a button to turn on F keys then turn it on immediately. Delete key alone should work, F2 is another button to get into bios.
Another way of getting into bios explained in manual chapter 3.2 is if miss POST phase is to press ctrl + alt + delete simultaneously and then press reset switch on case. Haven't done it this way so not sure exactly when you do this without a display to look at. Assuming when Windows begins to load or at login screen i guess. So try imagine when.
If still can't boot to bios try disconnect OS drive so it's forced to.
Hopefully you'll get to bios one way or the other. If you do, try undo the setting you did.