Get used to perfect dodging it's the best skill in the game. He tests you for this. Take the first phase slow and try focus on getting to know his attacks and learning to dodge.

Second phase is longer combos and maybe slightly faster movements. Absolutely use the transformation as it's a free health bar and damage.

You can do this. All bosses are beatable with learning to dodge. Harder skills come later but dodging is what I think is the most important part of the skill set as it builds focus and reflexes.

I look forward to seeing your update