How to make macOS and iOS connect to the stronger WiFi
If the one in the living room is connected to the main router via ethernet, just change it to access point only mode. Stop assigning addresses from this router. Set it to the same SSID as the other (stronger) router, and your devices should hand off to whichever signal is stronger at the moment. I have one router at home, plus two more in different areas, set up this way, and there are no issues. When I'm upstairs, devices connect to the access point; when downstairs, they connect directly to the main router, transparently.