If wifi works, LAN should work because they are in the same subnet.

You can check what is the IP address the PC got from the router. It should be 192.168.8.x as well.

Also check if it a DNS problem. You can ping 8.8.8.8 in your pc to see if it works. If it works but browser cannot use the Internet, it means DNS is not correct. Please set up a custom DNS in the router or your PC, e.g. 8.8.8.8 and 8.8.4.4