ASRock CSM Disabled Stops any Kyeboard Input

A few days ago, I upgraded from Windows 10 to 11 using a Rufus-created USB, with TPM and Secure Boot disabled. I formatted my SSD and installed Windows in UEFI mode.

Now I want to enable TPM and Secure Boot for anti-cheat compatibility. However, when I try, my PC gets stuck. Here’s what happens:

1. I disable CSM in the BIOS.
2. I save and exit — the system restarts normally.
3. But after a second restart, the PC freezes on the ASRock loading screen. I can't enter BIOS or use the keyboard.

Notes:

• Fast Boot is OFF
• TPM and Secure Boot settings remain unchanged (OFF)
• The problem starts only after the second reboot following CSM disable. Save and exit seems to get me into windows 1 last time.