I’m not 100% sure what you’re looking for or how much smartthings integration you need, but the two systems that offer affordable facial recognition are Netatmo and Nest. (Expect more after iOS 14 launch is with HomeKit support for local facial recognition, which is a very impressive feature.) Also, ring recently filed a patent on a form of facial recognition, but that could mean two years out given their past timelines.
Of these two, Netatmo does not require a subscription and has better smartthings integration, although to be honest, not that much integration.
Netatmo also has an IFTTT channel for the camera, so you can get a little smartthings integration that way as well.