Hazbin Hotel was picked up by A24, so I imagine either they're working on new episodes but keeping quiet till they're released somewhere, or waiting till A24 sorts out where they'll go.

The only problem i have with Hazbin Hotel is that we only have a Pilot episode. while it's spin off show Helluva Boss has 4 full episodes. Don't get me wrong i like the content, but it seems like the team is focusing more on the side project than the main event.