I don't want to lock up the diff. I don't want to lock up the slipper either.

The way the decoupled slipper works, it puts more power to the axle that has the most load on it (the rear under power and the front under braking), and it makes that end slip the most. In theory it would allow for better grip,
but in reality I want the truck to stop pulling wheelies when I gas it. And I want it to stop getting nervous and wanting to swap ends when I hit the brakes.

That requires that you un-decouple the slipper, so you get two (or if your are using the basket, three) discs dedicated to slipping the whole drive train as a unit rather than some unknown random percentage being split between the front and rear that you can't control. This fixes the wheelie problem, and makes the truck more stable when you get off the power.

It's your truck, do what you want with it. Just because you don't perceive that the problem exists, or you perceive that you aren't effected by that problem, does not mean you don't have it and it's not real.

It's not like if you don't like it coupled you can't pull out the roll pin and go back to the way it was before....