Running a campaign set in the Underdark

Right now I am prepping a game set in the Underdark where the players are playing as Underdark denizens. I have a lot of ideas, but what I keep getting hung up on is how to run exploration. Do I try to run it as one large dungeon/pointcrawl, or run it more like an overland campaign but with an Underdark coat of paint? I really like the idea of having this metroidvania style map with unique zones which connect in specific ways. I feel like it could be very fun mapping out rooms and having everything be constricted to a defined play space, but the idea of stocking and then restock every room they come across with interesting encounters doesn’t sound great. I’m not really sure which direction I should go in, so I’m looking for advice.