I wonder if that issue with no Ethernet during internet recovery can be solved by using an adapter with a chip that doesn't require drivers on Mac.
I have 2 that work on M1 Macs without installing anything
* Anker 3x USB + Ethernet with an RTL8153 chip (they don't make the hub anymore, but there's others still using that chip)
* Anker USB-C Ethernet (model A7613) with AX88179A chip
We bought a load of Anker USB-A Ethernet adapters for our new office, and with Big Sur they all stopped working. At the time I think Anker didn't provide the new drivers, and the chipset manufacturer themselves required you to also install an app to enable the adapter. Really not a good experience for our users, and we're slowly trying to get rid of the adapters.