There are a two details that might be unexpected for somebody used to the deb,
When you ujse the deb, you see in the GUI:
Path to the folder on the local computer. Will be created if it does not exist. The tilde character (~) can be used as a shortcut for /home/elopio.
When you use the snap, you get:
Path to the folder on the local computer. Will be created if it does not exist. The tilde character (~) can be used as a shortcut for /home/elopio/snap/syncthing/common.
So the meaning of ~ is different and that might be confusing.
Also, you can't sync hidden . files, nor files that are not in $HOME.
We discussed about making the snap classic, but it seems to me that we lose too much by removing the confinement. The ~ thing is an UX issue on syncthing, because the folder field shouldn't be a text field, it should be a file picker. And the file picker story in snaps needs to improve with content hub or file portal or something.
So the two problems we've found should be fixed, and they are not terrible.
Now, a tip for any syncthing newbie: make sure that your devices are in sync before traveling. I used to turn off my devices to save battery for the trip, and then add files and secrets to my desktop that would obviously stay only there. I was too used to the cloud magic.