@trendy I've lost the link to the owrt post I was reading earlier. I read there may be disconnect issues with AX88179 when used with RPi ?
Same post recommended AX88772C USB 2.0 or RTL8153/RTL8152.
Update:
found the thread
https://forum.openwrt.org/t/raspberry-pi4b-disconnecting-usb-ethernet/134696
@M10 Interesting solution. I don't have a managed switch to hand. I do have spare MT7621 and HH5a (Lantiq) routers running owrt which could be a suitable substitute? I would just need to find instructions on how to configure the VLANs etc.