16CH Analog Digital Multiplexer https://www.amazon.com/gp/product/B07K7JF3HX/
NodeMCUv1.0 Arduino Board https://www.amazon.com/gp/product/B081CSJV2V
Fielect 10k Fader https://www.amazon.com/gp/product/B08CD8QHR6
Updated to no longer use a switch. Just plug in with the first fader fully up to enter setup mode.