For reference, our monitor Lenovo Thinkvision P27h-20 has USB-C hub that works fine with my MacBook Pro M1, but I discovered a relationship between monitors "Super usb-c charging" setting and ethernet working or not:
Super USB-C Charging: On (90watt) - Ethernet not working, Macbook charges but connection falls back to Wifi
Super USB-C Charging: Off (65watt) - Ethernet working, Macbook still charges but at slower 65watt rate
I chose Super USB-C Charging: Off