@george1421 Thanks, that makes a lot of sense.
Yes, please, I would like to make a USB boot drive to try to get this working. How do I do that? I found an older thread of yours about it, https://forums.fogproject.org/topic/7727/building-usb-booting-fos-image
Is this still the best way to do it?

I am trying to deploy an image to a Lenovo ThinkPad 11e Yoga Gen 6 (type number 20SE) with a Lenovo USB-C to Ethernet Adapter (part number 4X90S91831, USB VID 17EF PID 720C). This laptop does not have integrated LAN, hence the adapter. MAC address pass-through is enabled in firmware settings, secure boot is disabled. Boot mode is UEFI native.

I am running FOG 1.5.9. The laptop boots to the FOG menu, using it’s own MAC address. But this is as far as I get. It hangs when trying quick registration or full registration. The last line on screen is http://[server IP]/fog/service/ipxe/init.xz… ok. Then an empty line, then it hangs. The same thing happens when I create the host manually, create a deploy task for it, and boot the laptop from the network.

I have tried:
Checking laptop firmware version, it is the newest, 1.08.
Adding the has_usb_nic=1 kernel argument
Kernel versions 4.19.143 and 5.6.18 from FOG settings, kernel update.
Fiddling with various BIOS settings

No change, it still hangs after init.xz.
I would be very grateful for any help or pointers in the right direction.