Long time Line6 fan here. I even got a Helix after I got a Kemper. Love both, its a great time to be a guitarist.
As I only play at low volumes I have always had great luck with studio speakers.
Recently I started driving a Katana with a single 12 and was surprised how good it sounded. It lacked the clarity and bass of my monitors but once you get a 12" up to volume it really starts to shine. Get that heavy low mid push. The Katana 12 had enough high freq to be useful in my case. I assumed a monitor would be much better. But the Katana stood its ground.
I have not tried a Kab, etc. Imprints sounds fun.
The amplifier is a major concern. If you want the profiler to do the heavy lifting, then you want the loudest cleanest power you can get. Since you are questioning your current tube setup, I think you are leaning towards a cleaner setup. I think this is another variable that puts people into certain camps. A Kemper/Line6 into a slightly driven amp sounds amazing and has insanely good feel! But it will not sound good for every profile right?
But my suggestion would be focus on the volume you play at. This is where amps and speakers start to run into issues.
Best of luck!