Multiple receivers switching

Hardware Radios
1

I’ve read manual and it says that it will switch only if there will be no pulses… FS_THR_VALUE will not work…
I have old-style receiver Arkbird 433mHz connected to rcin via cPPM and ExpressLRS receiver connected to telemetry port.

Is there any way to monitor FS_THR_VALUE value to monitor low values and switch to secondary rc link?

2

If you have an ExpressLRS reciever, why have an old Arkbird?
433MHz wont be long range or anything useful, its a noisy band of radio spectrum for everyones garage door openers and toys.

3

I need a backup rc channel as 900mhz can be jammed

Or can I theoretically switch rc input by lua script?