Potentially as much as none, because it's UV that does the damage?

At some point it pretty much becomes a microwave. Radiation get absorbed and turned into heat. On a small scale not very helpful or harmful. On a larger scale nice to heat your food with but not your head.

You'd have to be moving pretty fast to red-shift IR radiation into microwaves, I think.

I guess IR can be harmful (IR lasers, military grade IR LEDs). But yes, likely not the consumer grade IR LED.