It needs to be registered to your Google Home App for it to show up on your hub.
What happens when you use the Google Home App to Setup a new device?
May want to consider resetting and going through the process to Add again.
I apologize for my late response and thank you for all of your patience while waiting for a reply. I can definitely understand how frustrating your situation must be, but I wanted to make sure that your issue was addressed. Do you still need help with this issue? I know that there's been a delay in response since you posted.
Please let me know if you need further assistance.