As evidenced in the forum thread Tautulli been running fine but now can't start, the transition from Python 2 to 3 has been somewhat bumpy for Tautulli users on FreeNAS. The Tautulli FreeBSD/FreeNAS Installation Instructions lends itself to scripting, however, it leaves the Tautulli database in the jail. The hint on how to relocate the Tautulli database outside the jail is included in the forum resource FN11.3 iocage jails - Plex, Tautulli, Sonarr, Radarr, Lidarr, Jackett, Transmission, Organizr.

This scripted installation of Tautulli will create a jail, install the latest version of Tautulli for FreeBSD from tautulli.com, and store its data files outside the jail where it can be more easily managed.

Scripted installation instructions are at https://github.com/basilhendroff/truenas-iocage-tautulli.

Acknowledgements:

1. @danb35 for allowing me to reuse code fragments from his scripts and adopt his documentation style to facilitate rapid script development and deployment, and maintain a consistent look-and-feel.
2. @Pentaflake for the Tautulli data directory pointer.

References:

1. Forum thread Tautulli been running fine but now can't start
2. Tautulli FreeBSD/FreeNAS Installation Instructions.
3. FN11.3 iocage jails - Plex, Tautulli, Sonarr, Radarr, Lidarr, Jackett, Transmission, Organizr.