I have an Ender 3 V2 that I barely ever print on any more because I have a RatRig V-Minion now. I love this little monster, it's so fast.

The triangles are a result of the print "wall" changing thickness. Look at the corner on the left. All 10 perimeter lines go all the way round. If 10 go in and 10 come out, we need extra perimeter lines in the corner to fill the extra width. That's why there are triangles.

I imagine you could fix this by making the walls the same thickness at all points, but without trying I can't be sure.

I've not played Cult of the Lamb but Hades had the same effect on me. Love that game.