Does the Kasa KS200 work with HomeKit, Alexa, and Google Home?
The Kasa KS200 supports HomeKit natively and needs no hub.
You do need a neutral wire in the wall box. It suits HomeKit, Google Home and Alexa users, with native support through the maker's cloud. Home Assistant users reach it through an integration (the maker's cloud).
How the device gets into the platform on this route. The headline is the best route: local before cloud, direct before bridged, core before community. The methodology page lists every level.