Here are 11 right-angle lights with USB-C, a sub-lumen mode to preserve dark adaptation, and a standardized removable battery of some sort. If you can wait a couple weeks for shipping from China, the Convoy H2 with Nichia 519A LED for excellent color rendering is a good choice.
If the USB port can be on the battery instead of the headlamp, there are several good options using the 14500 (AA-size Li-ion rechargeable) and 18650 (larger Li-ion rechargeable) batteries which can be found with USB-C ports on them, such as this 14500 from Skilhunt and this 18650 from Acebeam. The Skilhunt H150 is an excellent 14500 right-angle light, and their H04 series are nice 18650 models. Nichia 519A LED suggested in either case.
If you can give up the sub-lumen mode in favor of faster shipping and USB-C on the light itself, the Sofirn SP40A is a reasonable option. I suggest it over the HS40 due to color rendering, though the latter has higher maximum brightness.