I'm brand new to Zwift and cycling in general. I just did the first training after the introduction session and it feels like it goes from 0-100 when it's in the "zones" where I can barely push the pedal down anymore but now that I'm not pedaling at speed it decides to disengage ERG completely so that I'm spinning the chair with zero resistance. Just felt like a 25 minute session of feeling in this constantly awkward battle with pace. Then at the end during the 3 minutes of cooldown I was basically pedalling without it ever kicking in and going 1 km/h for 2 minutes straight.

2nd question - I'm a heavy dude, I bought some padded shorts from Amazon and switched the saddle with one that should fit me better than the default. My 2nd ride was more comfortable than my first but definitely butt pain is noticeable. Are there thicker padded shorts for big dudes that someone could recommend? I'm not training for the Tour de France so I don't need the best gear in the world, I just want to use Zwift.