If you place torch under yourself and quickly break the torch (mainhand was empty) the "cracks" appear on it and save untill you start breaking any block. Consatntly doing this can lead to the block to be broken. I think it works with almost every block that can be instantly destroyed in survival/hardcore mode, but I've only tried with the torch.
P.S. I used OptiFine 1.15.2 pre 9
P.P.S. Launched and did same in vanilla the glitch works.