Hey HappyMushie.
Svas are indeed seasonal and transfer from season to season (passes over from reset to new map/season) If you do /crates and look at the Monthly crate that is there ( Zelda this month) you will see items in there that are named Seasonal vault Access..
Players also item them in chat and also if you look on server /ah you will see them in there. They usually sell for cubits and also players list svas on discord in the trade channel. I hope this points you in the right direction!