one question though, lets say my phone did get lost and I got a new one. Would I just put syncthing on the new phone to send it all back?

you will need to import those exported backups to your newly installed apps. You can't sync android's protected directories.

It helps to take a step back and think about Syncthing as a file sharing utility in general.

Syncthing allows you to share any number of folders with any number of other devices with any type of sharing structure you want (2 way file sync = filesharing, 1 way file sync = backing up). You can also set up file versioning on files within a Syncthing folder's settings.

Note: Syncthing is not intended to be a true file backup utility, and some people will get quite upset if you portray it that way, which I get, but also it just works... and you just need to be reasonable about how you do things, just remember it is a general filesharing tool that you are USING to backup files.

You are the cloud with Syncthing, but unlike something like Nextcloud there is no special central file server nonsense, there are just Syncthing devices sharing folders to other Syncthing devices so you can do it however you want. You do need two devices of course, your phone you want to backup and the device you are backing up onto (which could be a computer with usb drive attached), but from there you can add new devices and share the same folder/folders to them and leapfrog important files without needing to sit there and think out some complicated system or architecture ahead of time.

Syncthing is very "organic" because it is so simple, but it is also very powerful, I have relied on it for years in a variety of contexts and have never really been let down.

One tip, if you want your own personal cloud, a raspberry pi type device, or an old phone plugged into the wall can serve as your server that is always listening for file edits/updates from devices in a folder share. Otherwise you have to make sure Syncthing devices are on the internet at the same time to sync files, though there is actually a quite nice GUI interface for resolving file conflicts if they do happen (I have used it quite a few times and resolved issues).

If your files are smallish, just setting the "file versioning" setting under a Syncthing folder's settings to a number like 5-10 versions can provide even more confidence you won't lose something but I digress....

I love Syncthing!

edit you can also do weird little hacks if you need to by doing things like setting up a Syncthing folder share on a Dropbox folder to sync files in ways you wouldn't otherwise be able to do, it isn't a recommended practice but shrugs I have also done this many times too and haven't had any serious issues.