that wavelength penetrates the skin. you need to be around 222nm for human safety

uviquity has prototypes of a 220nm solid state chip they’ll commercialize next year (we’re an investor). a single far-uvc photon will destroy the covid virus.

https://uviquity.com/

Yes, however the safety-profile is quite the opposite to 222nm.

https://www.larsonelectronics.com/news/1763

https://uvmedico.com/far-uvc-light

This is Far-UVC (typically 222 nm). Regular UVC can cause eye damage.

Do you know a good source for finding the latest, most efficient LEDs for DIY projects?

This is an affordable 255nm UVC flashlight (buy filter separately due to US patent bs):

https://convoylight.com/products/gray-c8-uvc-255nm-uvb-310nm