I am also experiencing this issue. I've also done the same step as you did (Install base -> update -> dlc) and the game crashed when checking for DLC Content.
But the game would run just fine if I don't install a single dlc.
I've also added a file into the Atmosphere>contents>0100B04011742000
I...
guys i just checked to see what's in the fortnite item shop today and saw that metallica skins, atla skins and jjk skins are in the item shop at the same time rn, shit's not real