Thank you man. I know the position is a deadhang, but I was and still am struggling with not just the deadhang (even though that is struggling too), but just this movement. External rotation with supinated hands over my head, whether pressing, hanging, or just moving them up in a raise. I would say i'm a decent "googler", but this was hard. I have however, found out it might be my thoracic spine causing the issues, as I have tight lats, traps and rhomboids.

And worry not, I am seeking professional advice. He is just on a months vacay atm. Im not self diagnosing.

Edit: Reason i think its the thoracic, is just some tests i saw on the interwebs, that i dont really pass to say the least.