Unity is deprecating Built in Render pipeline in 6.5 version. https://unity.com/topics/render-pipelines-strategy-for-2026

Render Pipelines strategy for 2026
Discover Unity's focused 2026 strategy for render pipelines. Learn how we're advancing the Universal Render Pipeline (URP) for all platforms, maintaining HDRP with Nintendo Switch™ 2 support, and deprecating the Built-In Render Pipeline to simplify your workflow and enhance performance.