Can’t find a fractured wall for the life of me
I don't know where you are, tho i do recall having a hard time finding them the first time i went in at really, really low level ones. The first section does seem to be some kind of mine area as opposed to the real biomes.
I find them on most delves now. Tho there is no rush, the quest line isnt necessary. It basically just reminds you to upgrade each piece when it gets to a certain point, nothing more.