Rouvy Workouts and Rouvy AR both work as expected for me with my Wahoo Kickr 2018. I never use Rouvy to calibrate, always the Wahoo Fitness app. Suggest people with problems should calibrate using the software from their hardware manufacturer. Calibration settings are stored by the trainer, so it doesn't matter what software is used to do it.
Also should check that rider weight is correctly entered in any training app, since the default might be heavier and cause hills to be harder.
Having suggested all that, I think a lot of beginner riders don't actually understand what 5+% grades are supposed to feel like and are surprised how much harder it is to pedal...