What kind of LEDs did your uncle use? What wattage were the diodes? Did he use top bin COBs?

There are LED panels that have IR diodes as well as UV. That source in your post is also 5 years old, and isn't a legitimate case study.

I respectfully disagree with you.

Seeing the difference between the "blurple" LEDs, which are just blues and reds mixed, compared to a full spectrum (390nm-710nm) panel, definitely have me convinced there's a huge difference.