You can share here the mod file for verification pf NVMe DXE insertion, before flash.
EDIT: As long i can remember…theres no complains or issues affecting LAN after performing the NVMe mod with latest DXE_5 or Old DXE_4.
You have another issue, bad mod or something else you didnt shared with us…
I have followed this same tutorial and successfully flashed the modified BIOS, the module I used is NvmExpressDxe_5, but I have problems with limiting the network card to 100 Mbps.