Have you done a factory reset on your Kemper?
Make sure of the following cab related settings -
1. Cab section isn’t locked.
2. Output doesn’t have the cab disabled.
When it comes to level -
3. Input Sens settings aren’t too high.
4. Output level isn’t too high.
Neither input light nor output lights should go any further than bright green (any yellow at all means clipping on either input or output).
Remember as will all digital audio equipment make tonal changes and raise distortion and compression with the controls, not by driving inputs!
This means by using the gain control or compression in the Kemper and the level on your amp (either on the speakers or on your audio interface in this case) rather than pushing an input or output on either the Kemper or your audio interface.
Then check that some effects are disabled.
6. Pure cab is initially disabled (you may or may not like the effect on the tone).
7. “Space” is also disabled.
After that check your guitar and monitoring.
8. Are you comparing through the same monitors/speakers as the Kemper?
9. Do you have active pickups? Have you replaced the battery recently?
Finally once again you haven’t answered my question - have you profiled your own amps?