Dont be surprised, cause Intel bios mod were always trick ones… a bit to mod but more difficulties to flash mods.
They are AMI V Core bios…but more AMI Intel than the regular pure AMI bios…thats why.
You can try this tool: [TOOL] UEFI Editor - BIOS/UEFI Modding / BIOS Modding Guides and Problems - Win-Raid Forum (level1techs.com)
Any questions regarding this tool utilization post in there.
Be prepared for anything and even a broken machine, do suggest SPI backups and a programmer seems, in the past… the only way to flalh mods on Intel bios machines.