Do I need to charge my toothbrush via my monitor?

Searching for something like "USB-C OTG slim" will help find up shims that can be stuck in the end of USB-A Male plugs to "convert" them to USB-C, and from my testing just now, seems to work for charging.

The reliable thing about USB A is that it only produces 5V. And by "reliable" I mean safe.

Out in the real world, USB C is a minefield of dodgy electrical components because there are many different standards for a single physical connector. Sure if you implement the standard right, the hardware is safe. That's a big if when it comes to the corner store and supply chains where people with food instability have to compete on price.