A:AnswerBridge mode won’t help. Depends on what you mean by lose connection, if it is the satellite you need to move it closer or have a better line of sight.
A:AnswerThe ORBI systems are horrible to connect to 2.4ghz devices. Unfortunately most smart switches and plugs are 2.4. Look elsewhere if a Smarthome is your goal - ORBI is more for device connection
A:AnswerYes, the Orbi satellites support an Ethernet backhaul connection. More information about it can be found here: https://kb.netgear.com/000051205/What-is-Ethernet-backhaul-and-how-do-I-set-it-up-on-my-Orbi-WiFi-System
A:AnswerYes. You can hard wire the Orbi satellites.
It supports both wireless and wired for the backaul. You can also daisy chain the satellites or wire each satellite back to the Orbi router.