Could you elaborate a bit more on this ? I mostly have 2 use cases ... live with scenes and crucial functions instantly accessible (like delay hold, boost, modulation on/off , reverb on/off). And the other is a more freeform jam / writing session with all effects and various channels available through multiple switch presses.I have both an FC-6 and a GT/22. They are clearly different from each other. What isn't necessarily clear is that they address a different set of needs. There's overlap, but they are not 1:1 comparable in their features or intended use. I use them as required depending on the needs of the situation.
For sheer power-per-square-inch, I think the FC-6 wins out in an Axe-Fx III-only situation. But the GT/22 spreads more power over a much larger footprint and more complicated user interface.
The RJM GT 16 seems like it would do the trick but definitely looks like a lot of programming to achieve this.