Purportedly per Atlassian doc it should be possible to skip home zip creation when performing an unattended /automated upgrade. A home directory can become quite large so in real life cases not an option or very unpractical.
A manual upgrade will create a response file reponse.varfile with option
backupConfluence$Boolean=false
However, when you feed the installer with this option, the installer will still create the home zip!
There are more options that are ignored for example the option
launch.application$Boolean=false
will not stop the application from launching. BTW, this option comes from Atlassian documentation https://confluence.atlassian.com/doc/unattended-installation-838416261.html
The installer itself generates a different option
executeLauncherAction$Boolean=true
