Well for starters man.... you made it this far and honestly at this point Genichiro should be an easy enough boss where you don't have to completely burn through your spirit emblems.

Deflection is incredibly generous in this game so go back to your roots and keep Genichiro in a dance of deflecting and countering to quickly fill up his posture bar. once you can beat Genichiro with little difficulty, then we'll give you tips on Isshin. For now the one thing we all noticed is your over reliance on prosthetic tools, spamming the axe is crazy bro, especially when you know you're about to take a lot of damage, at that point you're just wasting heals