I got my Airstep Multi Controller working with my Player with the USB C on the Airstep going into USB B on the Player. I've tried the KPA preset in the Airstep app and changing rig works fine but I seem to have an issue with going up and down banks with long presses of the first two footswitches - it just keeps cycling through the banks continuously. Possibly a programming issue and I need to spend some more time with it. I programmed my own presets with functions to toggle effects on or off which works well
Haven't tried an expression pedal through the Airstep yet
edit: I got the Bank up/down working in the KPA preset - had to change the long press CC value to 0 instead of 1. Works nicely