Consider deprecating old core API

**Description**
Currently controllers lacks proper search support.

**Proposed solution**
Add configurable search with sensible defaults.

**Priority**: Low/Medium

Start by locating the controller entry points and the existing core API, then check whether any search implementation or configuration already exists. Clarify the intended search behavior, sensible defaults, and the scope of any API deprecation before changing code. Done means the agreed search capability and compatibility plan are documented and covered by relevant tests.

Written by the indexing model from the issue text.