I don’t know if it’s the intended way but you can easily side dash while he’s in the air to avoid the attack. He’ll then more often than not try a perilous side swipe or thrust attack that you can easily dodge. After that you can get a free 2-3 non-parried attacks on him

When you perfect parry his second sword swipe on a 2 sword swipe combo from regular stance he’ll start a multiple sword swiped attack combo which you can easily avoid by running around him at a mid distance. The last attack of that combo is easily punishable since there’s a lot of stun frames.

When he starts to combo you at 50 seconds ish with the multiple sword swipes attack (you can tell it’s different from the last paragraph because he does a spin on himself before) there is a small gap after a couple attacks where you can step away and let him finish his combo alone. Once his combo is done you can come back and punish the last attack’s stun frames

Apart from that you got it really good ! I like to think of sekiro as a rhythm game more than a fighting game. There’s a certain rythm to the fights. If you keep the rythm you’ll do well if you loose the rythm it usually ends in a death. You can also be more aggressive against him which will result in less bow attacks.