When installing Python 3.10.9 with the following command as SYSTEM;

python-3.10.9-amd64.exe /quiet InstallAllUsers=1 PrependPath=1

The resulting installation path (C:\Program Files\Python310) isn't added to the system PATH variable. As indicated in the documentation (https://docs.python.org/3.10/using/windows.html); PrependPath=1 should add the installation directory to PATH. This was previously working on previous version of Python 3.10.