The plugin acts only as a bridge; you still need the actual SAGA software (binaries) on your computer. Installing the "SAGA Next Gen" plugin in QGIS

To use SAGA GIS tools in modern versions of QGIS (version 3.30 and later), you must manually download and configure a third-party plugin. SAGA is no longer integrated as a core provider due to frequent API changes that made maintaining it within the standard QGIS package difficult.

Open QGIS and navigate to > Manage and Install Plugins .