Firstly I apologise for my lack of knowledge but I am just starting this journey.

I fly VFR light aircraft on VATSIM with x-plane in VR.
I donít need a home cockpit as Iím sitting in the virtual one. But it would be nice to have a physical button to tune the radio. Well thatís where I started, then I began to learn what could be done with a Teensy.
So now my project is to start with a coaxial rotary encoder for the radio and learn from that, then gradually grow the ďcockpitĒ to around 10 encoders some coaxial,30 buttons and 10 switches.

Iím happy with writing the code but the hardware bit is all new to me.

What I could do with is some guidance on is how the numerous outputs (around 70) generated by all these controls get connected to the Teensy, or do I need multiple Teensys, or am I barking up the wrong tree.
Some very basic guidance please.