32.7.3 is BSP version of Jetpack 4.6.3, the corresponding DeepStream version is 6.0.
JP4.6.3: JetPack SDK 4.6.3 | NVIDIA Developer
DS6.0 installation guide: Quickstart Guide — DeepStream 6.0.1 Release documentation (nvidia.com)
btw, you can also use SDKManager to install deepstream.