I know that some of the community members do you use it heavily.
If it is any assurance, Kong’s Ingress Controller also uses decK for configuration management in Kong.
There are no known bugs in decK that I’m aware of (that doesn’t mean that there are no bugs in it).
It captures all the entities except credentials like basic-auth, key-auth in Kong.
decK will work with one workspace at a time. You can easily script it to backup and restore each workspace inside Kong Enterprise. decK is a community first tool but is compatible and extensible enough to work with Kong Enterprise as well.