In the very first side quest of God of War Ragnarok, you will be asked to deactivate 3 towers in In the Service of Asgard, including the Tower of Modvitnir in Svartalfheim. The catch is that completionists will end up with an empty line and no matter how much they turn around, they won't find anything: here's why you shouldn't bother with that just yet.
The principle of treasure maps
It's a bit weird how it works, but this mechanic was already present identically in the previous game. Basically, to complete the empty rows in your progress list, you'll need to find a treasure map elsewhere first, so the item spawns in the indicated location. A functioning that leaves some doubt, but which will at least have the merit of explaining a lot of things when you wonder why certain completion rates are not 100% even after careful exploration.
Svartalfheim Treasure Maps
We recommend that you avoid the article that reveals their location and where to find the treasures: these cards are only distributed in the last part of the game and if you are looking to complete the tower, you are probably passing through during the Quest for Tyr chapter. Everything in its time, you will eventually be able to clean everything in the corner, but for that you will have to wait about fifteen hours to obtain the tool that will unblock the situation. For those who don't care about the spoiler, the treasure map walkthrough for this region is just below.
The first GoW boss you face in Control of Atreus is a giant grandmother you try to steal the cauldron from, it's not glorious. Here's a written strategy guide with tips and tricks for defeating him on maximum difficulty, as well as a video of the fight in this mode.