A missed win is worse. Blunders happen to everyone and ruining a possibly won game is much, much worse.
Which is worse? Blunder or Missed Win?

a missed win cause the game would have ended if you hadnt missed the final punch
I once got a missed win in the first 10 moves of a game

It seems that a missed win can be triggered with just a couple points of fluctuation from the evaluation bar. Is this a mistake?

A missed win is worse than a blunder because this gives a small chance for a different person to win when you are winning. A blunder is something you an come back from though. you can't really come back from a missed win.

A missed win is where you can win or gain a huge material advantage, but you missed it.
A blunder is when you made a move which actively damaged your chances of winning.
The big difference is that you're still in the game with a missed win. Even if you could have found a faster mate, you still mating. With a blunder, you are done if your opponent noticed.

I think a missed win is worst because missed win is a good opportunity that you missed like a good position, piece advantage and perhaps even checkmate.
A missed win does not necessarily mean we missed a check mate. If we had an opportunity to win a piece and we didn't take it, that counts as a missed win. So a missed win could be anything between acquiring a bishop or a knight to the queen or the game itself.
Similarly, a blunder is when we gift our piece(s) to the opponent or a let him take a powerful position on the board.
Hence it depends on each case as to which is worse. If the missed win was to take the queen or a check mate, obviously thats the worse thing to do but if it was just missing out on taking a knight or a bishop and the blunder we are comparing it to is about losing our queen/giving up a powerful position then the blunder is costly. But as noted earlier, games tend to continue after a missed win and usually ends in our loss when we make a blunder.

A Blunder is 100% worse! It means you either gave up a free piece to your opponent or gave a huge enough advantage for them to win the game. On the other hand I have had plenty of "missed wins" especially in blitz, where I still win the game. A missed win means you had an advantageous moment/move in the game you missed that could have possibly ended the game sooner, or even just netted you material.
I was wondering whether getting a blunder was worse than having a missed win.
Also, because a missed win is a blunder, when is a blunder considered a missed win by chess.com?
Correct me if I'm wrong, but getting a missed win is better for your game accuracy than getting a blunder.