Currently, there is no unified standard for NTR, at least no law has stipulated it. You cannot convince me, and I cannot convince you. Everyone has their own preferences and expectations, and no single work can please everyone.
As for this game, the character settings of Inoda and Asuna have already hinted at the direction of the story. From my personal understanding, Asuna's "love" for Inoda is inevitable, or to be more accurate, not only her body but also her heart will be taken by Inoda. It's somewhat similar to the NTR route in Spiral Legend V.
Vanilla? To some extent, yes. But it's based on a twisted love and a conspiracy. Even if it's gorgeous and charming, it cannot change the reality that it is an evil flower. Asuna may eventually learn the truth and have a moment to mourn her once pure and innocent self and immaculate love, but she will ultimately fall into Inoda's embrace.
Will Asuna become a public whore? No, not in this work. If you like group sex plots, there are plenty of Doujin like that.
Will Kirito become Othello or the Count of Monte Cristo? No, he won't. Either he continues to be ignorant and happy, or he becomes a pitiful loser who enjoys being cuckolded.