yes this is not pure 5e dnd this is a video game call baldur's gate 3, this information I gave you come from the official wiki and can be tested in game.
I did just test it.
Hag who has been hexed to have disadvantage on Dex Ability Checks: 50% chance to hit with Sacred Flame. Rolled 1d20 in the combat log.
Hag who has not been hexed: Also 50% chance to hit with Sacred Flame. Rolled 1d20 in the combat log.
Conclusion: Hex doesn't affect STs
Of course, this might be a bug specific to hags, or Larian might
want disadvantage to affect all 3 of STs, ability checks, and attack rolls but have not implemented it yet.
You are correct - Ability checks and Saving throws are totally different things, and Hex is designed to target only ability checks. Nothing in the game indicates that the spell has been changed to target saving throws (the only thing that's changed is the duration)
Here's Jeremey Crawford's
ruling on it.It'd be way too overpowered as a level 1 spell if it can affect saving throws. Imposing saving throw disadvantage is super rare in 5e as it's one of the most devastating debuffs. There's a reason why people think the College of Eloquence Bard subclass is extremely OP is because they can do precisely that.
how often do you see the monster in bg3 roll Ability checks ?
but in a way I was right , disadvantage does affect ST in some cases , just not the hex spell , right ?
like if you are blinded, how can you safe VS the fireball coming in your face?
but accoring to the rule , blinded state does not affect ST but all ability checks.
but Paralyzed,Petrified,Prone,Restrained,Stunned,Unconscious all creature automatically fails Strength and Dexterity Saving Throws.