@Sebastian-Roth while poking round in the BIOS on some new Dell machines I did find an option called “Force PXE on next Boot” - https://www.dell.com/support/manuals/en-uk/dell-cmnd-config-v3.0/dell_command_configure_cli-v3/-forcepxeonnextboot?guid=guid-85c17652-4a18-4538-8665-e6b3e777d649&lang=en-us
You have to have the dell tools installed, but this would be a possible option.
I know with my current machines when a BIOS update happens it keeps overwriting the boot order so my PXE boot doesn’t happen. Quite annoying!
I don’t know how I’d go about making the FOG Client execute this command before a task reboot though.