First of all… its AMD and AGESA/PSP is not easy at all…
You may try this tool: [TOOL] UEFI Editor - BIOS/UEFI Modding / BIOS Modding Guides and Problems - Win-Raid Forum (level1techs.com)
Anything related post on that thread.
Good luck
EDIT: Not sure, deep code and not readable on current avaiable/“Leaked” tools maybe…
Im no coder/bios engineer…sry.