This might help you. I have highlighted everywhere you can walk without activating key. There are zero features to get you on a wall. What else can you do in this minuscule space? What fits?
Loving those edits as the realization sinks in. G really takes it up a notch. G-flower-flip is infamous. I gave some advice for that elsewhere in the thread.
And the author has another step-magic game called sea magic. It's easier IMO.