....What? Stealth is not that useful? Stealth surprise attacks literally grant you 4 separate free surprise turns on each character before you even start the fight, what are you even on?
These are merely surprise attacks. You can sneak up to them by avoiding their vision cones, even in the heaviest armour. No stealth abilities needed beyond clicking the hide button. You don't need Pass Without a Trace, you don't need Blessings of the Trickster. You don't need invisibility most of the time. Just surprise them from behind.
Stealth is not useful in this game in the sense that enemies that you have stealthed past will just join in the fight later on, such as the four masked people in the Hag's lair, making it more efficient to simply kill them on your way to the Hag. You are actually punished for stealthing past them because you would then have to fight them AND the Hag at the same time.