Hi RexPan,
Can you see the Hyper-V Manager in the start menu? Run msinfo32 and see if the hypervisor can be detected.
Check if there is any other virtualization software installed on your computer. If yes, uninstall it and try again.
Also check if there are any third-party antivirus or security software that may be blocking Hyper-V. Try disabling them temporarily and see if that helps.
Refer to this link to enable Hyper-V on Windows 11
Step-By-Step: Enabling Hyper-V for Use on Windows 11 (microsoft.com)