Can any ipad attach ethernet to my router?

This Ethernet adapter works with recent iPad models (as listed in the description).

The Belkin USB-C to Gigabit Ethernet Adapter - Apple

I’m not sure the iPad can house whatever software/firmware you need to set up your router. That’s a different issue.

The following may help: https://9to5mac.com/2020/04/01/how-to-use-ethernet-with-ipad-usb-c-lightning/

Also note that many routers can be set up by using an app without using an ethernet connection. One example: https://www.tp-link.com/us/support/faq/1971/