In the new architecture, a device can only use an edge driver if the “fingerprint“ of that device is in a driver which has been downloaded to your hub.
When you can add a device to your Account but it only shows up as a “thing“ that means no drivers on your hub have that fingerprint.
IF you can find a custom driver that does have that fingerprint, you can download that to your hub, and then you will be able to change to that driver in the SmartThings app.
How do you find a custom driver with that fingerprint? You can try the quick browse lists:
FAQ: Using the quick browse lists without the community wiki
Or you can search the forum for that device name.
If you can’t find one, then you can request that a community developer create one. There’s a thread for that. Make sure you read the first post carefully, because there is some information that you need to post with your request. No guarantees, but if it’s A popular device or uses commands similar to another device, you may get a response.
Post Requests for Zigbee Edge Drivers Here (community-created)
So once you have a matching edge driver on your hub, it’s pretty easy to switch. The hard part is the research you have to do to find one or get someone to create one. 