try one of the linux OS - HiveOS/RaveOS/Simplemining

Upgrade bios to newest (important in case of problems)
Set boot device to USB/pendrive or HDD/NVME depends of your disk
Enable 4G encode
Set PCI-E support to Auto
Enable onboard graphics (PEG -> IGD)
Plug your monitor into the ONBOARD graphics card
Optionally enable S5 sleep support

boot with one GPU and add one at a time if all goes well