Perfected for whom is the question. Fingertip sizes vary quite a lot, so it seems unlikely the same cutout will work equally well for everyone. I suppose the huge cutouts as seen on the Mous Limitless and Otterbox Defender are the safest bet, but boy are they ugly.One brand told me they went through 15 or more revisions of the cutout but they perfected it.
Assuming a functional design, the solution is clearly a capacitive button cover…