Well, there is one thing I forgot about the older Spektrum/LemonRX Satellite receivers. Most of them need 3.3V and are not tolerant of 5V. It has been a good while since I've hooked one up to something that didn't have a dedicated DSMX port. I started digging deeper and there is no 3.3v pin on my speedybee f405-wing FC or Matek Fxxx-wing FCs. The newer Spektrum satellite RXes are tolerant to higher voltages.
My Diatone Mamba F722-wing does have a 3.3v breakout.
What are the exact make and model of dsmx receivers you plan to use. You will need to double check their voltage requirements