The point wasn't American casualties - the point was Japanese casualties. For example, of the 25,000 Japanese soldiers on Iwo Jima, how many survived? A couple thousand, maybe? So, based on that shining example (and similar percentages at the other places I mentioned) one could have reasonable assumed, beforehand, that they were willing to fight to the bitter end at Okinawa. And, because there were many more Japanese soldiers on Okinawa than Iwo Jima, one could have also reasonably assumed there would therefore be many more American casualties. You see how this works?
The bitter fighting at Okinawa should NOT have been a surprise to American war planners and it certainly did not alter their plans with regard to the nuke. The nuke had taken YEARS to develop, it had been intended with Germany specifically in mind, but circumstances dictated otherwise. So, your statement that "It was never intended at [sic] Germany" is complete, unadulterated b.s.
“The point wasn’t American casualties”
Yes, the point was the American casualties.
Okinawa was a shock as American losses were an order of magnitude higher than at Iwo Jima. And, as I’ve already demonstrated, allied losses at Iwo Jima were considered high for the war. Do I need to cite contemporary opinion stating exactly this?
Okinawa in May after VE day was followed up by the push (by Truman) for the Trinity experiment, followed by the subsequent dropping of the bomb on Japan. The timeline fits together well. It matches up with contemporary opinion of the shock of the American battle losses at Okinawa being larger than the entire rest of the war in the pacific up to that time.
The historical account simply doesn’t support your position, sorry. Okinawa was a shock.