Consider deprecating old controllers API

**Feature request**
It would be great to have filtering for lib.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_filtering` with default `false`.

Start by locating the lib directory and the existing controllers API, then trace how configuration options are defined and consumed. Clarify what “filtering” should filter and which old API behavior is in scope; done should include an agreed behavior and the new enable_filtering option defaulting to false.

Written by the indexing model from the issue text.