This may seem like a really stupid question and maybe I have missed something along the way but here we go, Kylo is looking for the wayfinder on mustafar where Vader’s castle is also located right but wouldn’t you expect the wayfinder to be hidden in Vader’s castle and not out his back somewhere?.
I know it may seem like a bit of a stupid question but only just really thought of this lol.
It’s an answer that takes a lot of vague canon stuff.
For one, the wayfinder was supposed to be under the protection of the Eye of Webbish Bog, who would have needed to be submerged in water.
For another, these particular cultists were obsessed with returning Mustafar to its original state, when it was a lush garden. As a result, they wanted to hang out in the forested area. Look up Lady Corvax if you want to know more.