Enter the fight with the goal of not attacking. Just watch the boss, learn their tells (telegraphing), and practice dodging.
Each weapon type has unique Arts (special attacks). Map these to your comfortable buttons and use them to break enemy shields.
Afterimage Trainer: Mastering the Art of Metroidvania Combat
For players who want to practice specific scenarios, test builds, or overcome frustration, an external "trainer" or cheat engine can be used. These tools often provide features such as:
Enemies have weaknesses to different damage types (slashing, piercing, blunt, elemental). Swap weapons based on the enemy type.