I feel like this is a common issue in Kemperland, and there is no "one size fits all" solution. Everything suggested in this thread is good to try. Here's a few more:
- Try completely disabling Pure Cab, not just turning the value to 0.
- Try switching from over-the-ear headphones to in-ear monitors. I now use Shure SE215s which made a positive difference.
- Experiment with enabling/disabling the Space parameter (it is supposed to add "air" into the sound with headphones to better simulate hearing it in a room I think.)
To be honest, I do still experience that feeling of sameness in profiles though, especially since I tend to favor British style amps with similar characteristics. So you are not alone.