Trying to understand what exactly you're trying to do. The bulb and motion sensor are on the Hubitat hub correct? Then there is another wifi bulb on which hub? Hue hub? ST hub? HubConnect can link those hubs to hubitat and you can replicate the devices over. HubConnect will sync the virtual device with the real device.
Alternatively you could create a virtual switch along with a rule to turn off and on the switch when motion detected and when not in Hubitat and a routine in Alexa to piddle with the light.
You could also just bring the wifi bulb over to Hubitat. I have some Kasa RGBW wifi bulbs connected directly to Hubitat via the LAN.
Also might want to look into loading Hubitat Package Manager. Makes installing popular apps a lot easier.
