How to enable secure boot on Windows 11?

Hello,

I am the owner of a PC running on Windows 11 with an Asus Prime B560 Plus motherboard. I am trying to enable secure boot, which I was previously able to activate when I upgraded from "Windows 10 to Windows 11," but I am now facing difficulties. The secure boot option is available, but once I enter it, there are only three settings: "secure boot state" greyed out on User, so I cannot modify it, "os type" which I can switch to "Windows UEFI mode" or "Other Os," and "secure boot mode" which I can set to standard or custom. Another tab available when I activate "Custom" is "key management." I tried changing the mode to Windows UEFI, but when I do that, the USB ports, and by extension my keyboard and mouse, are no longer detected, leaving me stuck on my PC’s login screen. However, upon rebooting, the keyboard works for a while, allowing me to enter the BIOS. I want to clarify several points: all my drivers are up to date; CSM is disabled; the "Legacy USB" and "XHCI Handoff" settings are enabled, I do not have the "Platform Trust Technology" or "Intel Platform Trust Technology" options, and my BIOS is indeed in UEFI. I find myself in a deadlock and therefore request your assistance.

Attached is a screenshot of the BIOS. Best regards.