Installing the missing VC++ will only fix the “Could not load the Windows BLE DLL BleWin10Lib.dll” error message above. If you’re not seeing that it’s probably something else.
One thing to try is adjusting the privacy settings in Win10 under “Other devices” → “Communicate with unpaired devices”. Also you can try unpairing the device from your PC if you paired it outside of Zwift.
If I had to guess from your “Bluetooth Radio NOT Found” error message, for some reason Zwift’s Bluetooth DLL doesn’t like those dongles. That doesn’t make sense but some of the Amazon reviews of CSR-based dongles (which claim BLE support) have warnings about not being able to pair with some devices. I haven’t had that problem on the systems I’ve tried but they’ve had “normal” built-in bluetooth (macOS, iOS/iPad, Qualcomm w/Win10).
Your comment about not being able to reach a human is unfortunately par for the course for venture-backed companies. They like to invest in “scalable” companies, and guess what isn’t scalable? Hiring humans to provide support. And apparently fixing long-standing UI/UX problems 
In any case sounds like you were able to get the ASUS adapter working - hopefully that has been stable for you.