If you search the Armortek forum for single stick control or single stick motor control you should find the information you seek. I and several ther
members have posted on this subject several times. I use the FrSky Taranis x9d+ for this same purpose as well as the FrSky X20HD.

The mix is not complex and is easily accomplished on the Taranis when using OpenTx OS (Companion) or ETHOS OS with the FrSky
X-series radio handhelds. If you decide to go with other brands like Jumper- Now Radiomaster or Helloradio they use EdgeTx which a is more capable development of
OpenTX - however creating a mix is much the same.

A mix doesn't need to be that complex to effect the control of twin motors; most often though there's a shortcoming when making a turn when in reverse but manageable.

I happened to find an OpenTx Companion screen print I made some years back of an early version of the mix definitions I used for my Armortek M3 Lee.
Channels 3 and 4 are the two channels used and on the left stick. Some variation of this would be common across all systems. This was used on a Taranis as I recall.

Bear in mind you need to define the inputs and outputs.



Jerry