For three, provide dev-placed map markers for all the important stuff - shrines, quests and all quest objectives, cave entrances, Zelda flashbacks, etc. Don't just rely on players placing inaccurate pins based off what isn't hidden by terrain from their perspective.
For minor collectibles, like Korok seeds or the glowing frogs, use a 'Guiding Wind'-style function to gently guide the player to their location.
For minor collectibles, like Korok seeds or the glowing frogs, use a 'Guiding Wind'-style function to gently guide the player to their location.
For two, split the large map into individual regions, unlocked via story progress - so the player isn't utterly overwhelmed by a giant-ass map from the get-go, and still has a decently sized area to explore at their whim. Ghost splits the island of Tsushima into thirds, following this philosophy, and it works excellently.