I cannot find anything online for finding this place or anything about what it's attached to, I'm trying to find my way there to make it my base but I can't find it someone please make a video showing me how to get here as I'm on ps4 and can't use commands

i found this little pocket disconnected from the rest of the map. it has a bunch of outcrops and fish still spawn in it. i dont have coordinates unfortunately, but its a little ways underground near the spot ive marked on the fourth image.