In the far southeast Ligneus Region, under the Sivash region I found that climbing on this snowy peak goes over the invisible walls and you become really out-of-bounds. I saved a video going straight through the water and you fall through the ground, but if you go around the edge, you can go into the Auruma region before it's unlocked. I don't know if there's something there for a glitched run, but I thought I would leave this here for anyone willing to mess around with it. I played with it a lot, but was having difficulty entering back into bounds in the Auruma region.

Update: I found a 2nd OOB southeast of "Isolated General Store Ruins", east of the teleporter which is south of the Store. If you climb up you can get on top of the area by climbing a ladder hidden in the back, going over houses, onto a wall, and then jump onto black rocks and make your way on top and head towards the distant mountains into the black portion of the game map.

Update 3: I got two 30 second video captures when I got over the invisible wall and how I managed to skip into the Lacuna region when it was locked. This means there's a skip into the Lacuna region officially. I will upload soon.

Update 4: Video collage of different 30 second captures on the Switch.

I was able to unlock a significant portion of Lacuna, so it's more or less accessible minus some things.