Advice for a portable, usb-c, 17.3" touchscreen monitor?

I’m looking for a supplemental screen to use with my 15.6" Galaxy Book Flex. There are a reasonable amount of 15.6" monitors that are usb-c powered out there, but I want a 17.3" one. This seems very hard to find, if I also want it to be a touchscreen. I want to be able to move around, mobile, and have a big touchscreen monitor that I can plug into my laptop anywhere. Why is this so hard to find?

-17.3" touchscreen
-usb-c powered
-good color gamut
-400-500 nit brightness