There's so much inspiration they could draw from. A catastrophic opening event creates a separate dimension kind of like the upsidedown in Stranger Things which can only be accessed through gateways (could use the depths for this) and has brought into Hyrule a plethora of new monsters.

This catastrophe could instead split Hyrule into pieces, forcing the player to traverse from island to island by water or flight (similar to The Wind Waker) adding underwater swimming and exploration to the series, which would be an absolute game-changer! (literally!)