You may encounter this problem, even if Virtualization is enabled on your PC (in the BIOS) and shows up as enabled in Task Manager (as seen below) and Virtual Machine Platform + Windows Hypervisor Platform is Enabled. The solution is:
1.***Remove WSA***: Right clicking on "Windows Subsystem for Android™ Settings" and pressing uninstall + Deleting the extracted WSA (MagiskOnWSA folder that you extracted and installed from) + Go to %LOCALAPPDATA%/Packages/ and delete the folder: MicrosoftCorporationII.WindowsSubsystemForAndroid_8wekyb3d8bbwe
2.***Go to "Turn Windows features on and off" and disable Hyper-V, Virtual Machine Platform, Windows Hypervisor Platform, and Windows Subsystem for Linux, then restart.****
4.***Ensure that you have Control Flow Guard enabled in Windows Security > Apps & browser control > Exploit protection.*** This is a known issue that can prevent WSA from starting