Guild Wars 2

Hi ! i have stealth gliding in HOT, but would i have to redo all the gliding masteries for tyria?

No.
“Once gliding in Central Tyria is released, anyone who has completed or later completes the Basic Gliding Mastery will be able to deploy their glider in not only the Heart of Maguuma maps, but in any open-world map in Central Tyria as well. If you’ve unlocked other gliding Masteries like Lean Techniques or Advanced Gliding, these will also function in Central Tyria. "
https://www.guildwars2.com/en/news/gliding-in-central-tyria/