why does it say "missed win" here?

thanks, he wouldn't let me kick his queen off b4 though, unless he also took my queen.
I do see now though how black could have had white's queen trapped in one move of a rook Rd8, and I see now that by attacking his queen with c3, then if he trapped my queen with his rook and was ready to take my queen then if he killed my queen I could kill his queen.
you write "By kicking the Queen off b4 " <-- he's not going to let me do that though, unless he could also take my queen and he wanted to trade queens.
you write "Moving the pawn up doesn’t capture material immediately but it opens the opportunity to do it in the future on e7 and b7" <-- The c3 pawn won't help capture material on e7 though, i'd need the f pawn for that and it has quite a way to go.

you write "By kicking the Queen off b4 " <-- he's not going to let me do that though, unless he could also take my queen and he wanted to trade queens.
No, he couldn't.
You play c3 (blocking the check and attacking his Queen). Now he CAN'T play Rad8 attacking your Queen because you will simply TAKE the Rook with your Queen, and after he captures your Queen with his other Rook (or Bishop) you will take his Queen with your Pawn.
Now count pieces : you lost your Queen. He lost his Queen AND a Rook.
He can't do that.
What did you mean when you say "By kicking the queen off b4".. If you mean me taking his queen with my pawn, i'm saying he's not going to let me do that(unless maybe if he's positioned to take my queen too). If you mean stopping his queen from checking my king, then I agree that's a good move I missed or didn't choose.
I agree that if I had played c3 and he'd done Rad8 attacking my queen and i'd taken his rook and he'd take my queen and i'd take his queen then i'd be at an advantage in that exchange.

white's a piece up and therefore winning. after Kf2 black plays Rd8, whites Q is trapped and white's losing. instead, c3 attacks the Q forcing it to c5 ( still protecting the B and attacking the N twice ) whites N then retreats to safety and if Rd8, the Q's no longer trapped as it can capture the pawn on b7 and escape.
why does it say "missed win" here?
https://www.chess.com/analysis/game/live/5922255699?tab=analysis
it says "missed win", it is not keen on where I moved my king. But then its suggestion(moving my pawn one space forward), wouldn't win me anything! (sure it attacks his queen but he can move his queen out of the way easily)