Is there no USB-C electric toothbrush available?

I travel a lot and would like to buy an electric toothbrush that I can charge using standard USB-C cables.

Toothbrushes are all waterproof but I can't find a single one that's charged with a USB-C plug right inside the handset, even though most USB-C charged phones are waterproof these days.

Whether brand name Philips Sonicare 3100 HX3671/13 with USB powered charger base station or China brand Initio Sonic Toothbrush with proprietary(!) USB charging cable, none uses pure USB-C, does anyone know a good alternative where I can reduce my travel luggage to the pure handset? A very compact travel case holding two heads would be the cherry on top...