10G USB-C Ethernet adapters are now a thing... just ordered one ($87 shipped to US), probably will run out of first batch quickly: https://www.wisdpi.com/products/usb-c-to-10gb-ethernet-adapter
10G USB Network Adapter | USB3.2+ Realtek RTL8159 10G RJ45

@geerlingguy Hope you'll post a review. I saw a similar one at $60 (same chip) but I'm hesitating to order.