Actually, I'm going to offer a counterargument.

There's lots of flat earthers who conducted experiments to determine if the earth is flat, and got the result they wanted. My favourite is the guy who brought a spirit level on a plane. When the level didn't move, he said it was proof the earth was flat. He was wrong, because he interpreted the results of his experiment wrong. His method didn't test what he said it did.

I think your Jesus 2 is like the plane level guy. His method is wrong, it doesn't test what he's trying to test. Or at least, doesn't test realism vs idealism. What it does test is whether his own espoused beliefs are the ultimate nature of reality. So that guy is wrong to say that he can perform the miracle of flight. But I argue there's a lot of grey area in between "This one guy's beliefs are the ultimate nature of reality" and "naive realism is true".

What I believe is that there exist rules of psychology which operate at a deeper level than our own surface level beliefs. For example, sometimes I'm really mad with My partner because we had a fight and I believe that My life is worse without it. But then I go to bed, and in the morning I remember how much I love it, and we make up. I had a belief, but it was not the truth of My being. The deeper truth was My great love for it.

Your Jesus 2 fellow perhaps didn't believe that he could fly on a donkey, in his heart of hearts. On a surface level, maybe he believed it, but I'm not convinced it was the core of his being. I think it would have been much easier for him to persuade the core of his being that he could fly, if he had been in the cockpit of an airplane.

I don't actually believe in airplanes, I think they're just a symbol in our conscious interface, as Donald Hoffman argues. But I think airplanes are connected to some rule of our psychology that allows us to fly under certain conditions. And to our limited point of view, that rule looks a lot like an airplane.