I am also having issues with the resistance on the Atom Next Gen.
I can recreate the issue by selecting a flat route and slowly build up my cadence to around 70 rpm to warm up, but changing gears doesn’t make any difference to the resistance or the watts produced.
I can increase my cadence to 100 rpm and change up to 22nd gear and I am spinning out. The gears are showing on Zwift they are changing, but not the resistance.
If I push down hard on the peddles and increase my cadence quickly the resistance kicks in and the gears work properly.
I also get the same issue going down hills in Zwift where I am spinning out and the gears aren’t working and then when I hit the bottom of the hill and the gradient changes the resistance kick back in.
I have recreated the issue using 2 different ipads and a WIN10 laptop.
The bike is in an out-building which is 5 meters away from the house. There is only one other BT device in the building which is an Amazon Echo. The bike is about 3 meters away from the wi-fi point in the same room. I have a full wi-fi signal of 70mbps. I have closed all the apps on the Ipad.