which is worse Blunder or missed Win

If we're talking about playing skills then blunders are worse in most cases because they are usually easier to spot

i'd say that most of the time missed wins are worse because it could lead to your opponent checkmating you after you had the blatant chance to checkmate them first and end the game, but blunders shouldn't be worse unless it's severe, or you've done multiple ones in a row. you can still win games with both but missed wins make the game more difficult to continue.

It depends on the outcome. Either could take you from a winning position to a losing position and either could be relatively inconsequential because you're still in a winning position. Try to make sure that you spend your time converting winning positions into wins and forgive yourself for rushing moves which don't affect the result.

Blunders eat at me worse because I notice them more.

I don't mind when my opponent is just better than me, I DO mind when I stupidly hand my queen over because I was overtired and not really paying attention.

A blunder might be giving away a queen by not seeing the opponent's discovered attack, while a missed win could be not realizing that you have mate in 5. The blunder is clearly worse.

A blunder is a bad move, a missed win is a move that is not bad, but is not the best move. A blunder is worse.