PC stopped displaying after enabling XMP on first boot – B550M AORUS ELITE AX

I just built my first PC and I'm having a weird issue.

Specs:

• Gigabyte B550M AORUS ELITE AX Rev. 1.4
• Ryzen 7 5700X
• RX 9060 XT 16GB
• 2x8GB G.Skill Trident Z DDR4-3200
• 750W PSU

The PC booted perfectly on the first attempt and I managed to get into BIOS. I enabled XMP for the RAM, saved and exited, and since then I've had no display. I never go to installing windows, I’ve just been trying to fix this.

The PC powers on normally, fans/RGB work, but the monitor stays completely black. GPU is connected directly to the monitor.

I've tried:

• Clearing CMOS (battery + CMOS pins)
• Both RAM sticks individually and together
• One stick in A2 / both in A2+B2
• DisplayPort and HDMI
• Reseating the GPU
• Checking the 24-pin and CPU 8-pin power
• Booting with no RAM installed — still powers on but no display

I also used Q-Flash Plus with the correct BIOS for Rev. 1.4. The QFLED blinked during the process and eventually stopped, but I still have no display afterward.

The PC has never booted into Windows — the only successful boot was the initial BIOS screen before enabling XMP.

The motherboard doesn't have CPU/DRAM/VGA diagnostic LEDs, and I don't have a motherboard speaker for beep codes.

Could enabling XMP have caused this, and what would you try next? I'm wondering if it's still a RAM/POST issue or possibly something else.