Hello drumrhyno,
I fear that the USB B to C adapter is the faulty one here.
Do you find the MiniLab MKII in the devices list (either in Audio MIDI Setup -> Midi Studio or in About this Mac -> System Report -> USB) ?
My though are that you will not see it, because you're adapter does not forward the USB data cables correctly.
Are you able to successfully use the adapter (for a real use, not only powering/charging the device) with another device which also needs data ?
Can you try the same cable with any other USB Midi Controller or even your phone ?
I truly think that's not a MCC issue, but a cable/adapter issue.
If we found that the MCC is the faulty guy in the story, I will totally try to reproduce your issue (maybe you can link me the reference of your adapter) and fix it.
Thanks !