From my experience, many profiles might be somewhat mix ready or close to it which means that some lows are not always prominent. When adding a tube screamer type pedal externally, you're removing more bottom from a profile that's intended to be tight already.
One solution is if you need to use an external pedal because you like the character of that pedal would be to use the amp parameters in the Kemper. I've had a lot of luck by reducing the "definition" significantly. Try it out and if it's still not as tight engage "clarity" to about 3 or 4. Don't forget that Tube response also can be lowered to give more of a tight preamp response verses loose power amp if increased.
Dean_R
Thanks for the tips. Been playing around last night and this has helped a little.
I’ve pretty much taken the rigs back tfrom basics and built them from the amp up again. And I’m closer this time. Have to be really careful with the boost level. I think you could get away with a lot more into a valve head.
I found a balance of an actual increase in definition with an increase in sag and adding a good slug of clarity and pushing the tube shape towards power amp seems to have given me some of what I’m looking for.