Allow an option to maintain grade based resistance during workouts

I want the see the interval timer and the target power, cadence, text alerts, etc. during a workout, but I want the normal grade based resistance changes as a normal ride since that is the best way to prep for actually racing outside.  As it works right now I have to run the structured workout on my normal cycling computer to see the interval timer and targets, and just do a normal ride in Zwift.  There could be 3 options for workouts - “Erg mode” “Trainer Curve mode” “Normal Terrain mode”