I have a Neo2 and have ridden Zwift, Rouvy, FulGaz, and Road Grand Tours. Every app has a different resistance feel and slope increase/decrease feel. I have ridden 7 different Rouvy rides with big climbs and didn't notice an unmanageable amount of resistance when doing climbs. My gearing is 50/34 with 11-32 cassette, I like to spin when climbing. I would agree the resistance seems more than what you experience with Zwift for a similar slopes. So you aren't imagining things IMHO. I just haven't experienced any climbs in Rouvy where the resistance was so over done that it was overwhelming.