@fishfox While I find your post quite interesting I reckon it is just making it more complicated in this case here. I wouldn’t go down that road myself.
@Zer0Cool As you already know most boot ISOs are a bit different and there is no simple solution for all of them. A lot do work using the memdisk but it’s causing trouble often enough.
I guess you might find this quite helpful: https://github.com/tianocore/tianocore.github.io/wiki/Configuring-PXE-Boot-Servers-for-UEFI