https://docs.syncthing.net/users/tunneling.html
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Port Forwarding for Headless Machines
"My main use case for tunneling has been to access the web gui of my primary Syncthing node but SSH tunneling can be used for any other program presents data from a specific port on a remote machine."
With thanks to the author
Port Forwarding for Headless Machines. In my quest to find a DropBox like solution for local file sync between my machines, I found and fell in love with Syncthing. It is an excellent piece of software that gives you total control over how your data is synced and has proven itself to be extremely reliable. I will cover my Syncthing setup in another post but for context here; I maintain one master node running on a headless CentOS 7 virtual machine (VM) on my server and all of my other machines sync to it.
You're welcome.
I don't think you would necessarily have to disable anything to access the GUI from localhost. Which is what you would be doing with an SSH tunnel.
Adding a password and forcing HTTPS should then be done before changing the configuration to allow access to the GUI from the network.