yeah, you could show some kind of place of interest on the begining or smthn, and then guide the player towards the objective of the map
there is a game that did something like this and it's worth checking out i think Rate Demon's Revenge by Ka3aKa, FrozenDevs, SciathDev for Blackthornprod GAME JAM #3 - itch.io
don't know the dev but the game is great, and it has a portal that shows where you have to go, to destroy some objects before it gets opened.
just an idea
if you want to focus on full exploration, a way to know where you've been would be great, like some mark on the floor, or objects that change on interaction or when the player comes near them
i didn't knew there was a boss D: i got to try again