Continue Owl Father fight or move on the next

I am playing Sekiro and I also watch guide on youtube.I know maybe I should not watch it but the game is so difficult I dont even know if I would even know where to go sometimes without it.I beat the "early" ending and have save and continue to play to get other ending.Now I am stuck on Owl father fight in Hirata which is required for one ending .Should I save the game and continue to get other endings and then come back or just fight him until I beat him if its even possible lol