As I actually like Kirito, I can say that pretty much is a happy ending for him, especially in such an overly specific NTR situation as the one of that video, and honestly, it's even fun in its own way...technically the 'NTR guy' in this case WON. Nishida got himself Asuna as a wife, fucked her, had her carry his children, and then died content after living a fulfilling life with no issues nor regrets, THEN 'reality' slammed itself down on Asuna afterward.
Meanwhile Kirito remade his life with another of the several other girls around him and moved on like a healthy normal person despite receiving terrible emotional trauma, instead of becoming a cuck, killing himself, or randomly suddenly having every girl around him stolen randomly because the world stopped making sense, which I can appreciate of the author of even the original video, the world isn't running on NTR logic, is exclusively centered on Nishida getting a magical Hypno App, and he doesn't even abuse it to get himself every woman around Kirito to completely ruin his life for no logical reason, he gets the girl he wants, he gets all the money he would need, then fucks off to live his happy life fucking Asuna every day and be content with that without worrying about Kirito or what he does with his life anymore