I'm a welder by trade, and I often use flashlights to inspect my work. I've used a bunch of Maglite solitaires for a while, but I'm getting a little tired of how fast they gunk up or burn out. Turns out, welding work is ROUGH on flashlights, especially if you keep using them through grinding and polishing. What I'm looking for is a small, very durable flashlight. Preferably under 1" in diameter, between 3 and 5 inches long, and very durable with regards to heat and abrasive, conductive dust. Ideally, I'd like something usb-c rechargeable, but without some kind of dust flap for the port I don't see how that's possible. The other problem I tend to have with the maglites is that I end up melting the plastic cover over the bulb. That let's in dust, burning out the element. The front cover would probably need to be something other than plastic. Replacing the solitaires isn't the worst thing in the world, but it's a pain in my ass to forget to buy more and end up burning out the last one when I need it. I don't need anything particularly bright, just indestructible.
I work in the aerospace industry. So not as dusty as your environment. However I do use this flashlight around our engines after they have been running. It comes with a rotatable collar that acts as a dust cover. But it's not USB C, it uses micro USB.
https://www.pelican.com/us/en/product/flashlights/tactical-flashlight/7600?sku=076000-0000-110&gclid=CjwKCAjwq4imBhBQEiwA9Nx1Bk_9OJc0wiuCM7XrzCOq6E-krr15CP6DNJLrGnSXPB0jpj6t_AONrxoCaREQAvD_BwE&gclsrc=aw.ds
Rotating collars are death to tools in an environment like mine. You're just asking for abrasive dust to chew in there.