Tethering USB 2.0 / Canon 5D Mk III | Not working on Capture 20 + Catalina

I've read the support / knowledge base articles regarding tethering supported cameras with C20 and Catalina, but am still unable to tether a client's Canon 5D Mk III. 

MBP 2019 Maxed out - Catalina 10.15.7 - Capture One 13.1.4.15 - CalDigit TS3+ dock - USB A cable.

Tried multiple configurations, multiple USB A->C converters, multiple tether cords, and 2 copies of the Mk III body, etc... 

Cameras are able to be tethered to older machine running Sierra and Capture One 12. 

Thoughts?