Acoustic form works well and can work as well as rockwool, but like rockwool you’ve got to use enough of it and in the right places.
2" thick rockwool place directly on the wall won’t be great either.
And yes the idea is to absorb the reflection equally across all frequencies If you just absorb the highs andleave the mids stil reflecting and responding you can make the room worse.
At least use 4" thick foam or rockwool and mount it away from the wall so there’s a 4" gap behind it, or at the least 2" gap. Absorption right next to the wall does nothing as there’s no air moving there, so its’ waste of material