so this is still a problem and you are getting no love from rouvy?

It is actually a problem that my friend has. We tried doing same climb on Rouvy: around 5% grade, I rode on a medium gear (34 front, 18 rear), my friend was on his easiest gear (34 front, 32 rear). I was producing 130W with cadence 80 maintaining low speed, around 8kph. My friend on the lightest gear was incapable of continuing with me, because he had to produce more than 300W with a very low cadence just to keep up with me. Strange, as we both have Wahoo Kickr Core, same firmware, same Rouvy version.

what is the setup? Phone (what kind), COMPUTER (what kind). What else...allpe TV? These aer other differences that may play a role.

Have you tried calibrating your trainer?
support.rouvy.com/hc/en-us/articles/10720842424593-Calibration
Here is a link to the ROUVY page where it is all described.

Riding 34x18 at 80rpm in real life would be at more than twice the speed that you're seeing on Rouvy. Either your trainer is badly miscalibrated or your settings are wrong on Rouvy, like wrong weight or not actually using your Kickr Core as a controllable.

I might be remembering the speed incorrectly. My setup mimics real world perfectly in Rouvy and I enjoy it. It's my friend's setup that has problems - even a small grade climb in Rouvy makes it impossible for him to climb even at the easiest gear. What matters, it looks like he isn't the only one that has such a problem and I found a workaround solution for him to use wheel circumference adjustment as a way of adjusting gear range in Rouvy. Someone else might find it helpful.

This works beautifully!! Thank you so much.