Follow the guide, specially point#4
Set the system to a full PURE UEFI environment, if the system uses an EFI compatible card. CSM OFF not AUTO/ON, secure boot can be set to enable after 2 reboots.
Do not clone old OS, i advise you to perform a clean OS new install.
When doing so, disconnect all other disks, after setup and first 2 reboots and essential system drivers installed, you can attached them again.
Any disk/adapter will negotiate only @ PCIe 2.0 xX, PCIe 3.0 x4 only in 1rst PCiex16 when using iGPU. These are the limitations on these old boards.
I used till Jan 2024 a Maximus V with same cpu and W11 without no issues at all… for a very long time, doing all kind of use of the system.
Good luck.