Oh well the d-pad didn't seem to work for me in the menus then.
Sadly I know all to well about Unity's situation with inputs. I recommend you switch to Rewired on the asset store, it's a great plugin that comes with a button remapping system, although I haven't tried it out yet, I'm pretty impressed by the rest of the plugin. Word of caution though, the documentation is a bit lacking on how you set it up, but once you do get it going it's great.
Yes I do recommend a square instead, but if you watch Sebastian's videos on it you'll see that he uses a different approach entirely, but it ends up behaving just like a square collider.
Another thing I forgot to mention in my initial review is that the in-game menu for inventory and stats is pretty janky to use, so I would suggest you re-think your approach to that.
Thanks for responding so kindly :)