RC Passthrough - using standard radio control transmitter?

I’ve been using the herelink data link a while now and although I like the ‘RC’ controls for a quad or for a camera gimbal they are obviously not as good as a ‘real’ RC transmitter set like a FRSky / Futaba etc.
Currently I still have real RC on sbus to my cubes and the Herelink is only bringing me the video and telemetry back.
I would like some way to ‘bind’ my RC transmitter and the Herelink GS together to use the Herelink RC channel from the GS to the Airborne and onto the cube / flight controller.
What would be best would be a dual system where my RC is direct when within say 1km but then goes via the Herelink once the aircraft gets greater than ‘n’ km from the ground unit, this is to allow the real RC to control the aircraft at longer range than the RC can if its required.
I also have pilots who are used to their RC transmitters and do not wish to use the ‘drone’ gimbals on the Herelink GS.
It might be I have to use a USB lead rather than wifi or come up with some way to send Sbus ‘passthrough’ from the GS up to the Air unit?
I also have a ‘realflight’ RC simulator usb transmitter (spektrum) and the realflight simulator allows the use of a real RC transmitter with an adaptor lead - pretty much the same thing.
anywhos - I know what I’m trying to do is rather custom but there are a lot of RC aircraft and drone flyers who are very used to the RC transmitter they use and they would like to use that via the Air units RC / Sbus channel if they could.