I have a main router in my house that, unfortunately, I cannot change the configuration on. I also have a TP-LINK Archer C50 router running OpenWRT in an outbuilding. They're connected via powerline adapters and smart home devices (lights, outlets) are in both locations. The issue I am having is that I cannot "see" the smart devices in the outbuilding when I am connected to the house WiFi and vice versa when I am in the outbuilding.
My understanding is that I need to update the OpenWRT router to pass DNS and DHCP requests to the main router. One of the guides (https://openwrt.org/docs/guide-user/network/wifi/atheroswds) requires changing upstream settings, so I can't use that.
I have tried another multiple times (https://openwrt.org/docs/guide-user/network/wifi/relay_configuration), but the result is that I either cannot connect to the OpenWRT router, or the WRT router cannot connect to the internet.
Should I be trying the Replay Configuration guide again? Am I SOL with being able to see devices on both ends of the connection? Any guidance would be appreciated, thanks