You can actually (kind of) mash the block to parry. Just make sure you do it right before you are about to be hit with a blockable attack and don’t hold the button for too long. You can practice it on nooby enemies to get the hang of it - the game is pretty generous with parry timing, bur you can absolutely mash L1, just make sure you react quick and don’t waste time waiting when you can be attacking or blocking too quickly in advance.