Optimize controllers for large datasets

**Description**
Currently handlers lacks proper pagination support.

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

**Priority**: Low/Medium

Start by locating the handlers or controllers responsible for retrieving large datasets and inspect how they currently load results. Define where pagination configuration and defaults belong, then verify that large datasets are paginated and that the defaults are sensible.

Written by the indexing model from the issue text.