My wife and I both ride on Zwift using the same wahoo bike signing into the old app and at the beginning of the old app you just chose which rider was going to ride and it would immediately populate her or myself. we are both subscribed members and when I signed onto the new app I had to put my email and password and my site populated. We use a monitor and Apple for TV and everything is worked well in the past I could not see anywhere in the new app where you could switch riders i.e. going from me to my wife and then carrying out a ride. Could someone run through where in the app is the switch rider because when I close the app and open it it only recognizes me and I see nowhere to switch riders to my wife.
Try to force close the app and start it again. You should see the screen where you can switch users. This screen didn´t change with the new UI.
Edit: Always force close the app on ATV!