Just wanted to provide some input for newbies, being one myself. I had probs getting my Kickr to work with my Felt bike’s cassette. Issue: My bike had a 9-cassette, Kickr comes with a 11-cassette. Despite the advertised claim that Wahoo works with anything; do not believe that. Do yourself a favor, just swap the 11 for a new 9 and everything will run well.
Zwift worked as advertised! As for pairing to Zwift, there were no problems other than I initially tried to do it with a Windows 10 laptop (that didn’t work). Using my iPhone 10 to pair up quickly/seamlessly did work.
Now am riding more and more. Great job Zwift.