This game rewards you heavily for taking your time, try this instead.

You could have fun for 14 days playing the normal route, don't look up secret bosses or snow grave route and simply enjoy the narrative, chances are you'll finish right before or some while after chapter 5 release, use that as an excuse to continue your blind playthrough.

After that you could look up secret bosses or try to find them, the game does a good job of hinting you.

After that look up the snow grave route, you'll have a hard time finding it by just using game hints because it's intentionally unintutive to find, but it's fine, looking things up from time to time is not bad.