You can still use Unity Hub on your main workstation. Simply use the Locate a Version feature within the Hub's "Installs" tab and point it directly to the executable on your external drive.
Download the specific target platform installer (e.g., Android Build Support).
Inside the archive, navigate to the $_OUTDIR or root folder containing Editor .
UnitySetup64.exe /S /D=G:\Unity_Editors\2022.3.x