gltfpack

Start with gltfpack -i scene.gltf -o scene.glb and test the output in your game loader. Use -c for mesh compression or -tc for KTX2 textures only when the required decoder/extensions are supported. Optimization may change the node tree and references, so verify animations and names used by the game. The -kn, -km and -ke switches preserve selected names or metadata.

Sources: https://meshoptimizer.org/gltf/