Connect a lan cable and:
ip a (shows network interfaces and ips
ip a a 192.168.<subnet>.<unused ip>/24 dev <interface> (get the subnet from your router or phone WiFi settings, interface is the interface starting with "en" from the first command, for unused ip just try your phone IP +1)
ip r a default via <router IP> (router IP can be seen in your phones WiFi settings under gateway)
Also checkout /etc/resolv.conf, replace its content with "nameserver 8.8.8.8"