Under the new architecture, you can write smartapps in any language you choose, including Groovy, but Samsung is no longer providing a free cloud to run them. So you would have to host them yourself, either on a local server device, or at a hosting service.
There are a few people doing that, but not too many. Most instead are either moving their old Groovy smartapps to another platform that still runs them, like Hubitat. Or using a third-party app, SharpTools, which has a nice rules engine, and re-creating their automations there. Or just using the official features like the rules API, which has more capability than the old platform.
You can see more discussion about all of these in the following thread:
Replace Groovy with Automations—what’s your plan?
And here’s the official announcement thread about the ending of the old architecture:
(BTW, the IDE will also be shut down soon.)
So you can still have smartapps in the new architecture, but they run differently, and the integration path is different.
