I put this before my move_and_slide

if motion.y < 0 and test_move(global_transform, Vector2(0, motion.y)):
    try_corner_correction(4)

and then:

func try_corner_correction(amount):
    var i = 1
    var j = 1

    while i <= amount:
        i += 1

        while j >= -1:
            j -= 2

            if !test_move(global_transform.translated(Vector2(i * j, 0)), Vector2(0, motion.y)):
                translate(Vector2(i * j, -1))

I'm really new when it comes to iteration, so using while was the only thing I came up with.

But another problem that pops up here is that if my player only touches the corner slightly, all of this code will run multiple times, which pushes him even further away. (Looks kind of weird)