Tomoe Hitless (Charmless, Demon Bell, NG+)
An easy method is to go for 2 R1s during most punishes then react to whatever Tomoe's response is, since just like Isshin some of her moves have hyper armor. She has the fastest posture recovery in the game, but if you keep up the aggression and know which moves can be safely interrupted, you can prevent her from regenerating all of it.
A suggestion is to use Phantom Kunai to counter her input reading for projectiles. I also recommend using Flame Vent's Living Force since she is weak to fire.
Spiral Cloud Passage has to be one of my favorite moves to fully deflect, though Loaded Umbrella is very useful if you want an easier time. That said, she will recover vitality on block so you should still spin the Umbrella. Phantom Kunai can be used for triggering the semi-scripted first Spiral Cloud Passage. Another tip is that you can Mikiri the finishing thrust during her Phantoms for a big punish.
I love how you are heavily rewarded for surviving her most difficult yet still intuitive moves, it's a sign of great game design. Absolutely one of my favorite bosses from the DLC!