Nope, same thing. Bios setting maybe? Strange, had no issues before BigSur.
Yea check you're running latest BIOS version, also compare your settings with the list below.
BIOS SETTINGS (Bios Revision F12k & F12j Pro Wifi)
•
Enter BIOS -> Press Delete -> Enter Setup
• Save & Exit -> Load Optimized Defaults
• Boot -> CFG Lock -> Disabled
• Boot -> Windows 8/10 Features -> Win 8/10 WHQL
• Boot -> CSM Support -> Disabled (Can be set to Enabled if need be but try to have it set to Disabled first)
• Favourites -> Extreme Memory Profile (X.M.P.) -> Profile1
• Favourites -> VT-d -> Disabled (Can be set to Enabled or Disabled, Your choice)
• Settings -> IO Ports -> Internal Display Output -> PCIe 1 Slot
• Settings -> IO Ports -> Internal Graphics -> Enabled (Disabled If Using SMBios 1,1)
• Settings -> IO Ports -> DVMT Pre-Allocated -> 64M
• Settings -> IO Ports -> DVMT Total GFX0-Allocated -> 256M
• Settings -> IO Ports -> Aperture Size -> 256MB
• Settings -> IO Ports -> Wifi -> Disabled (Z390 Pro Wifi Only)
• Settings -> IO Ports -> Audio Controller -> Enabled
• Settings -> IO Ports -> Above 4G Decoding -> Enabled
• Settings -> IO Ports -> USB Configuration -> Legacy USB Support -> Auto
• Settings -> IO Ports -> USB Configuration -> XHCI Hands-off -> Enabled
• Settings -> Miscellaneous -> Software Guard Extensions (SGX) -> Disabled
• Settings -> Platform Power -> Platform Power Management -> Enabled
• Settings -> Platform Power -> ErP -> Enabled
• Settings -> Platform Power -> RC6(Render Standby) -> Enabled
• Save & Exit → Save & Exit Setup