I've been looking for a rule update on the original IG, and didn't find anything. For what i understood in the Outwit article of the 2017 rule update, all the "can't be countered" abilites turned into PROTECTED: Outwit. Is that what happend with the IG? Or it gives Power Cosmic?

So like it'd be like
THE GAUNTLET COMPLETE: Willpower, PROTECTED: Outwit; but only if all six Gems are attached.

That's what im not sure. Seems more fiting (mechanic and lorewise) to give Power Cosmic. While is functionaly equal, it can have some team build consequences.

That's not how rules work.

It is strictly giving Willpower and PROTECTED: Outwit (and even more technically, just giving "Protected: Outwit" to all the things, but not PROTECTED: Outwit to the character). While this is functionally very similar to Power Cosmic, there are things that affect Power Cosmic specifically. A character with Power Cosmic does not have Quintessence or Q Continuum, even if these are all the same abilities, so unless it is specifically giving Power Cosmic, don't treat it as such.

You had it right the first time, it's 'PROTECTED: Outwit'.