Syncthing and Upgrade path from native Truenas installation

[Gallifreyan]

I have 2 must have apps that I have installed on my truenas rn
Plex and Syncthing (to back-up to a synology nas that I also have)
so anything that would also work to back-up the same way would be acceptable (tho I now know how syncthing works, would be preferable)

I already have my TrueNAS set up with all my data on it, it would be great if I can upgrade using the 'update train selection' feature Truenas has for their different releases
mainly because I don't want to re-do everything... like my plex is looking good right now and having to try make it work with backed-up metadata would be a major pain
also having to copy all 25TB over again would SUCK