Exploring in the Archon Quest
While the (mini-)map might be covered in a black mist - this shouldn't pose an issue for progressing through the Archon Quest as the quest markers will still be visible and are within a short distance of eachother (shown below).
If the screen is too dark, you may increase the game's brightness by opening the Paimon Menu → Settings → Graphics → Brightness. The Lumenstone can also be used to lighten up the area around you and can be unlocked while completing the world quest "The Chasm Delvers". While progressing through this world quest, more and more areas of the map will also become visible, removing the black mist.