For what I know ...not all Arduino are equal on this ....micro Pro works natively as usb midi device tested on my Mac and it works with a a minimal effort.
MIDI control surface tttapa
https://github.com/tttapa/Control-Surface works great...the program should be configured with the proper control and it's actually not that difficult... the real issue is, for me to decrypt the Kemper manual to get the proper control number for your needs.
My dreams is to control delays real time while I'm playing with 12 real pots making dreamy ambient things...working on this .
Any additional sharing brainstorming or help on the issue will be appreciated.