exist a guide explaining all glitches/route for this game?

The strats are constantly being changed and optimized, join the discord. There is a channel w a lot of different strat videos

how would one join discord

Click the discord tab

how do you do bomb skip? the one where u dont need bombs to break the glass to go to the tunnel?

you need to shoot an arrow at a specific area where it will bounce off and hit the explosive barrels.

wedge yourself up in the door and copy the shooting angle from one of the current top runs. you should be able to get a feel for the area to aim for after some practice.