Have my wireguard client setup successfully. Using the command wg on my wireguard server, I can see OpenWrt is connected. On my LAN, I can ping devices behind wireguard interface if the wireguard interface is set in the WAN firewall zone, but if I make the wireguard have it's own firewall zone, I can't get through. Happy to post configurations, just not sure which ones...
If you want all lan traffic to go through the tunnel, usually the allowed ips in the peer config on the device will be set to 0.0.0.0/0 and ensure that there is firewall allows lan > vpn zone forwarding.