It is not a blunder, it is a conscious considered action on Fonald’s part, though it is spectacularly wrong and will have disastrous consequences. Nor are the people he had surrounded himself with less smart or successful than he his. The “climate change deniers” know perfectly well that climate change is real and that it is anthropogenic, but they are pulling a hoax on enough of their acolytes to be able to push through their agenda of personal and corporate profits.
A goal that reasonable secular humans consider to have horrific consequences for humanity (or “evil” in the judeochristianislamicmormon sense) is not a blunder. A mis-step in strategy or tactics to achieve that goal is a blunder. The Nazis’ desire for world domination was not a blunder, their invasion of the Soviet Union was.
I’ve yet to see a blunder by Trump that has any negative consequences for him, though it is indubitable that he is blundering about.