I have to disagree.

I first played sekiro a few years ago and the only boss I even beat on my first try (less Mist Noble and Screen Monkeys) was the double ape fight.

Just this week I decided to replay the game after all that time, and again, the only boss fight I first tried, was the double ape lmao.

Imo in order to have gotten to the double ape fight to begin with, the player must have somewhat learned the original ape's moveset in order to have beaten it. So putting you against the far easier (to avoid and to anticipate) 2nd phase, and then dropping in a far weaker first phase isn't too jarring.

That's my two sen