High Current Buck Converter with wide input voltage
The datasheet provides an example application diagram which shows it can output 8 amps at 3.3VDC which is 26.4W and it is far from 100W. But other than that this is my only concern.

Buck converter power levels don't work the way you think they work. If a buck converter can output 8A, it pretty much do that anywhere in its operating voltage range. The operating voltage range (and maximum stepdown ratio) are somewhat independent of that.
Besides, it's easier for a buck converter to step down smaller ratio than a larger ratio, and your ratio of 33.6V to 20V is much smaller than the application schematic's 24V to 3.3V.