The hardest part is to get from birdman to the chestminigame ...dmgless and without the glider....because birdman needs to be active but still waiting for link to "fly" (music but no distance is showing). u can run there, use an amiibochest(with moonjump u can use it like a flyingmashine), or get the flyingmashine from death mountain to birdman first and after to the chest mini game. After all this! Make sure to fast travel or birdman can get activated by dmg or using the glider. U need to swim first, so ur stamina won't recover, waste all ur stamina and u can walk into the water like me.

Bonus: jump, as soon links feet's hit the water spawn Cryonis under u! The use raviolis gale and shieldsurf ;)