Add firewall rule like this in luci:
10.0.0.2 is the wireguard client, 192.168.173.1 is the target IP which is not allowed for 10.0.0.2 client.
10.0.0.2 is the wireguard client, 192.168.173.1 is the target IP which is not allowed for 10.0.0.2 client.