There is no need to uninstall Tableau Server when running the tabadmin restore command. The tabadmin restore command will overwrite all data on the instance of Tableau Server where it is being run. To restore only the data and no configuration settings, type --no-config in the command. To keep configuration settings do not use --no-config in the command.
The Tableau Server license allows up to three (3) activations of the same key: one production environment and two non-production environments, as defined in the End User License Agreement. I recommend setting up a test Tableau Server environment and restoring the .tsbak file here. You can then download the .twbx and republish it to your Production Tableau Server using Tableau Desktop.