Question Motherboard no splash-screen or BIOS ?

Jul 2, 2020
I have an Intel i5 11400F (no graphics) on a Asus Prime B560M-A (BIOS up to date).

When I press power-on button a long beep and 3 short beeps sounds, besides that a white LED remains ON all the time. This problem is related to VGA (according to the manual).
After that a green LED turns ON (no video so far). If I press F1 Windows boots and when MoBo reaches logon screen video turns on (magically) but white LED remains on all the time (even when I can use Windows perfectly).

So my problem is I cannot enter BIOS or I don't have the certain since I don't have video.
The only way to get splash-screen and BIOS working that I discovered so far is using a CPU with integrated graphics but I don't have one anymore.

I really need to use BIOS to change some CPU and RAM frequencies and to enable XMP profile.
I'd really appreciate any help you guys could give me.