Currently there are 11 native Telephoto Prime lenses for Panasonic GH5S and 7 of these lenses are autofocus (AF) type.
Panasonic GH5S doesn't have a sensor based image stabilization system but 3 of these Telephoto Prime lenses features optical image stabilization.
Since Panasonic GH5S has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 4 Telephoto Prime lenses with Weather Sealings.