Help understanding how secureboot works on Windows

[CypherQc]

So I have the ASUS AM4 TUF Gaming X570-Plus (Wi-Fi) motherboard and I don't understand something about the settings

If CSM is off, it says in the bios that secureboot is fully loaded with keys, but then everytime I open the computer it brings me back to bios. 

If CSM is on in UEFI only mode, same behavior, brings me back to bios.
If CSM is  on and in UEFI + Legacy mode, it brings me into windows, but then windows tells me secureboot is not just disabled, but unsupported!

(For all 3 option settings TPM 2.0 and Secureboot options are left ON in the other tab in the BOOT submenu)

What do i need to be enabled to have secureboot enabled AND it let me load windows?

[Aree Soothsayer]

You are probably in legacy mode. Check this out.