Dungeons respawn completely after 150 minutes irl..

Entering a dungeon starts its regeneration timer. After the configured interval, the server regenerates that interior so its world-generated contents can be explored again. Player-built pieces, player characters and tombstones are preserved by this cleanup; loose, unowned objects in the interior are not protected.

Deep North spoilers — reveal

Morkhalla deletes any portals built inside on respawn, effectively requiring consumtion of key.