A blunder check you can use every move

You do not need a full analysis during the game. You need a check that fits in the time you already spend staring at the board.

First: did their move make a threat I have not answered? A check, a capture, or an attack on something that was safe. If yes, that threat is the move, unless you have something stronger that they cannot ignore.

Second: after my move, what can they take? Look only at captures. If one of them wins material, the move is not candidate.

Third: is my king on an open line with their queen, rook, or bishop? Pins and skewers live on those lines. If the line is open, name the piece in the middle.

Practice the check on easy positions until it is boring. Then use it in slow games only. Adding it in blitz before it is automatic just makes you late.