I haven’t really found the line colors or signal values to be of any practical use… reliability and resilience is more a function of the density of your mesh than the “moment in time” values presented by the map.
Include more repeaters in your mesh than you think are necessary. They are the literal backbone of the mesh. You should have a bare minimum of one per room and one in each hallway.
There are several articles in the Community Cookbook Index that cover various Zigbee-related topics.
Tuya Zigbee can be really hit-or-miss. If you find one of those devices to be unreliable, it is often best to just not use it… keeping malfunctioning routers powered on can wreak havoc on the mesh.