From what I read there are some issues regarding a portable version (the indexing requires a service to be installed).
Could the following be considered:
A “limited” portable version of which the directory switching and favorites menu works in portable mode. The indexing would not work and would require a full installation.
If there are other functions within Listary that could work in portable mode then add them in the portable version.
A Listary install through the command-line with the option to import settings (also through the command-line).
This is for example for work-machines that restore the machine after each reboot to it’s default settings but allows usage (installation) of external applications. It might be a bit of niche case, but this is just an example case.