I’m not getting involved with this one, but not having (very good) training plans, doesn’t make Zwift a “not training app”, you can get your training plans from multiple sources and do them in zwift, create your own (even better if you do it in trainingpeaks), create workouts without need for a seperate app, if you have a couch who uploads training workouts to Trainingpeaks (like some of sufferfest endurance workouts) then they download to the Zwift trainingpeaks folder and appear automatically
What makes a training app, is more complex than does it have a training plan (that may work for you)