That does look like a good light selection for the tank!
Curious though, could experimenting with a lens under the LED manipulate the light distribution as desired?
Places that grind eye glass lenses often have a box of rejects that were simply cut the wrong shape for the frame and would likely have a range of prescriptions to try that will not fit well under the light. Polycarbonate (most) lenses can easily be shaped with a wet grinding wheel if you mark the center and axis before you begin.
Maybe an uncut lens is a better choice?
Stock lenses are really cheap. If you find the prescription that you really like under your light, anti glare/reflection coatings are worth every penny. Not all coatings are equal, if you chose to get one, price is a good indicator of value or just get a hard to order Nikon lens.
That looks like a great tank/light/plant combo to try this with!
I like to set vertical driftwood on top of the roots and let it take to the wood naturally.