This happens on our Realm, unknown how it affects offline worlds but it likely does!

(We have Survival with achievements enabled and can't use commands or Admin/Moderator privileges)

Mining with single mouse clicks is faster than holding down the mouse button!

Steps:

  Place a beacon that applies Haste Level II status affect.

  Obtain a Netherite pickaxe with Efficiency V, Unbreaking III.

  Using the pick, mine through a large area of Deepslate by holding down the mouse button.

  Then mine the Deepslate using single mouse-clocks as fast as you can click.

Results:

  **  Holding down mouse click will have a lot of Pickaxe swings that don't mine the Deepslate  (as if swing-miss-swing-miss-swing-miss)

  Single-clicks will mine 1 Deepslate with every single click!

  Single mouse-clicks (as fast as you can click) is much faster than holding down the mouse button, and will mine 1 block with every click, versus holding the button will have a lot of "miss" swings.

Expected Results:

  **  Holding down the mouse button to mine the Deepslate should be very fast with Efficiency V and Haste II beacon effect.

  Holding down the mouse button should be equally as fast as using single clicks.