I tried the Asus forum, and they told me to come here.
I have an Asus Maximus X Hero (WiFi AC). (Latest BIOS)
I have a EVGA 3080 FTW3 Ultra Gaming 10GB.
Boot SSD drive is not a MBR format.
Tried new drive/Install, same results.

I have Fastboot off. I have CSM off. I have above 4G Decode enabled. Boot Mode in Windows UEFI Mode.
Had card on normal switch, X1 updated VBIOS.
Tried to enable Resize Bar in BIOS, BIOS reported "VGA Card is not supported by UEFI driver." after reboot.
No tricks worked, even reseating.
Switched the switch on Video card to OC, and it let me turn on Resize Bar in BIOS.
X1 updated the VBIOS, rebooted, and again, got the "VGA Card is not supported by UEFI driver."

Only thing I could find, is a utility GPU-Z says in Windows that above 4G is not enabled, but my BIOS says it is.

I am really lost on what to do next.

Sounds like PX1 broke rebar support by updating both of your vbios to ones which don't support rebar. You'll need to reflash both switch positions with a vbios that supports rebar to get support back. Don't trust PX1 to tell you if rebar is enabled or not. Only look at gpu-z & the nvidia control panel to verify if rebar is enabled. If both gpu-z and the nvidia control panel say rebar is enabled then it is regardless of what PX1 says.