Try to 2 hand your weapon and stagger them. Roll or block, then move to their back and try to get them in a stagger. Play unlocked more often, don't always stay locked on, it severely limits your mobility. You need to be able to move around and flank them quickly, and being locked on makes that tough, so manage your locked on and unlocked play.
Avoid swinging too much, or leaving yourself vulnerable with not enough stamina to roll away or block. Try your best to take out the First Gargoyle ASAP, then move on to the 2nd one. If you have Gold Pine Resin, use it to buff your weapon before you start the boss fight and it will add a ton of damage to your weapon.
