You can try changing the hostname and doing a ‘./launcher rebuild app’`.
But since the hostname has changed, a bunch of stuff in the database also needs to be changed. The easiest way is to restore a backup. There once was a topic about how to change the hostname; I don’t see it, but I might not have looked hard enough. Or maybe it wwas deleted because it’s much easier and more reliable to restore the backup.
You might be able to do a `./launcher destroy app;./launcher start app` and then restore the backup from the command line.
What I would recommend is Move a Discourse site to another VPS with rsync and Set up a staging server
Then what you’d do is push your docker image somewhere, and then use ./launcher start-cmd app to see how to start it. So you’ll need to figure out enough about docker to push the image to a private repo and start it up and then restore the backup.