speaking from pure logic, Renoise should realize which channel is being sent.
Most definitely for the keys, but what about the encoders?
If not switching channel along with the keys themselves (which is entirely possible), then you often have encoders grouped into “banks”.
Each bank = a unique set of CCs. This would make you have to switch banks manually - nothing Renoise can do to hold you in the hand there…
Look in the Instrument > MIDI tab, you can select your keyboard and then, which channel it should respond to.
You might also want to check out a tool I did for accessing these controls in a more streamlined fashion:
https://forum.renoise.com/t/new-tool-3-1-midiperformer/47001