Could you elaborate on why realtek was chosen for the ethernet expansion card? It does tend to have a pretty bad rep, with one of the recent documentations being
https://overengineer.dev/blog/2021/04/25/usb-c-hub-madness.h...Unfortunately, Realtek is the one and only choice for a USB 3.1 to 2.5Gbit Ethernet controller. We don't like it any more than you do, but there are several niches in the PC peripheral space where there is no alternative to using a Realtek part.
What about a Thunderbolt connection and a PCIe ethernet adapter - could that work?
The power consumption of this would be too high.