Regardless of wing or fuse or board or whatever, you have to determine what your geometry is. Measure it. See the youtube below. I am guessing the IQfoil on the SB 147 sets the wing quite far forward such that you can't keep the nose down when your board speed picks up. Is this what you mean by "overpowered"? The SB 147 has a freeride geometry, while the IQfoil has a more race-oriented geometry.
A friend of mine here has a SB 147 with SAB 790 and 900 fuse (freeride geometry foil), and he has zero problems in winds all the way up to 30 kts with a 2.8 sail. The wing is at the midpoint between his footstraps.
If your front wing is too far forward of the mid point between your front and back feet (footstraps or strapless), you will have this problem.