Node red after groovy?

Edge Drivers replace groovy device type handlers. NOT smartapps.

Edge drivers must be written in Lua and run on your own hub.

SmartApps for the new architecture can be written in any language, but you have to host them yourself on a hosting service or local server. We are not allowed to run them on the hub. So you typically have to connect to SmartThings via cloud to the REST API.

There are a few exceptions, like what @taustin has done for MQTT integration. He has a custom smartapp running on a local server.

If you would be willing to use MQTT as the go between between ST and Node Red, you could use his project. It has both an Edge Driver and a custom smartapp that you host yourself on a local server.

But if the Samsung Studio option @Automated_House mentioned is working, that would probably be a better choice. (For some reason I thought people had reported that that had stopped working late last year, but maybe it was a temporary glitch.)