Question GPU not giving video

[Carecara]

Today I upgraded the PC I had with a new PSU and GPU, moving everything to a new case (I've had this computer for about two years, about a month ago I upgraded to a Ryzen 5600, updated the BIOS and everything was fine).
Upon finishing the build, the GPU gives no video (though the RGB does light up). Mouse and Keyboard are unresponsive (and no RGB).
Fans, SSD rgb and HDD work fine.
Also: I can use the power button to turn on the PC, but I can't turn it off, the only way is using the PSU button

Any idea what this could be? Could the bios have "downgraded" to a previous version making it incompatible with the ryzen 5600?
SPECS:
ASRock Radeon 6800 XT
XPG Core Reactor 850W 80+ Gold
Asus B450 M-A
Ryzen 5600
2x8gb XPG RAM at 3200mhz
Case: Thermaltake V200 Tempered Glass Ryzen Edition

 

[Nine Layer Nige]

I would check all cables at both ends to ensure connectors are seated fully.
Also, check for shorting out of the mobo on the case (did a loose screw get trapped somewhere ?)
Does the mobo have error codes LED lights to indicate error or beep codes ?
Also, is there a light on the keyboard to indicate PC is actually running ?
I cant think why the BIOS would have downgraded simply due to GPU and PSU swap.
Have you put the RAM in the correct slots ?
Have you connected the 24 pin AND the 8 pin power leads ?
Disconnect as many non essential peripherals to eliminate issues.

 

[WolfMeister98]

Seems here the system wont boot up, try to clean gpu pci-e pin (mine using eraser) and the ram pin. Try to only boot with one ram slot, if it works then put the another ram.