You're welcome! Order flash programmer and SOIC8 test clip cable now now, it's cheap and everyone should have, especially if you want to mess around with mod BIOS or changing laptop graphic options. Best to order and have it on it's way then wait and order later.
To unlock your BIOS using my method, please Download
HWINFO64 and on the large window expand motherboard section on the left, look for ME section and get the ME Firmware version. Then from this page, in section "C", download the matching ME System Tools package.
https://www.win-raid.com/t596f39-Intel-Management-Engine-Drivers-Firmware-amp-System-Tools.html
Inside you will find a Flash Programming Tool folder, and inside that a Windows or Win/Win32 folder. Select the Win/Win32 folder, hold shift and press right click, choose open command window here (not power shell). Then run the following command and send me the created file to modify.
FPTw.exe -bios -d biosreg.bin
If you are stuck on Win10 without command prompt option (needs to be admin CMD Prompt, which above method will open, start menu way will not), then here is how to get it back
https://www.windowscentral.com/how-add-command-prompt-power-user-menu-windows-10-creators-update
https://www.windowscentral.com/add-open-command-window-here-back-context-menu-windows-10
https://www.laptopmag.com/articles/open-windows-10-command-prompt-administrator-privileges
Before you can flash back the mod BIOS I will send you, you'll need to boot to Grub and use setup_var to unlock BIOS lock. Here's a guide I wrote about doing this, you can start at step #6 because I've done steps 1-5 for you (info below)
https://www.win-raid.com/t3908f16-GUIDE-Grub-Setup-Var-Guide-Fix-Intel-FPT-Error-BIOS-Lock-Bit-Set-HSFS-W-Asus-or-Other-Mod-BIOS.html
Your BIOS lock variable to change in Grub >>
0xB3
Rename your .efi file to >>
Shell.efi
At grub prompt you'll type the following >> setup_var 0xB3 0x0
If you already know correct version of AFU that actually flashes mod BIOS for your system then we can use that instead of the above method. If you do know this let me know and I'll mod stock BIOS instead, otherwise we have to do as above or you'll loose your serial, UUID, DTS keys, and possibly LAN MAC ID too.
I can unlock this BIOS, so only waiting on your FPT biosreg backup
As for your concerns, here's the settings I see that can help once we get you unlocked
I think, enabling Chipset >> PCH I/O >> PCI Express Root Port xx >> Detect Non-Compliance Device set to enabled might help, whichever port is being used
Also, Chipset >> System Agent >> Graphics Config >> Primary Display (iGFX, PEG, PCIE) testing each of those may help as well. Below that, you can also set primary PEG and Primary PCIE. Also, in this section you can disable Integrated graphics if needed.
Additionally Chipset >> System Agent >> Graphics Config >> LCD Control - you can set Primary and secondary IGFX Boot Display (CRT, EFP, LFP, EFP2, EFP3, LFP2)
First setting I mentioned above, is also inside Chipset >> System Agent >> PEG Port Config >> Detect Non-Compliance Device, you can also enable/disable PEG here