Can't find multi timbral setting

And a few other options, I don’t know what your motivation is for how you hookup-implement encoders-knobs:

Use the Zynthian driver concept - introduced in NEW: Control-device manager + controller device "drivers" perhaps with an Akai APC Key25 mk2 driver
Use a touchscreen
Use a display and mouse
Build a Zynthian mini
Copy the Zynthian V4 or V5 circuitry (also uses 23017 as @wyleu suggested above.)

Just some ideas to consider.

Wow - I tried a search on Zynthian Mini - got: “An error occurred: Site is under extreme load, search is disabled, try again later”, so I did, and it did work.