Nietzsche's big work was moving German philosophy away from Christian thinking and influence he lost his career for his work Zarathustra for its attacks on Christian ideology he couldn't get hired in any university in Germany after that and they told him for that reason openly. I suspect more then one German philosopher hated Christianity and somewhat worked outside of it but didn't come against it because they didn't want to deal with the blowback.

Nietzsche's ubermensch is in all reality a person free of Christianity who follows their own inner self realization to self development and actualization without any self sabotage they are free to manifest the life they wish in accordance with their spirit. This allows the person to follow their natural ascending path which is the normal flow of the will of life in the universe this is also the obvious reason we have this normal thing called ambition. Its the desire to evolve within us in and become something more and whole of a being. This is what Christianity is at war with within the human psyche.

I suspect that Rudolf Steiner might be the origin of the Jewing up of Nietzsche's works. He showed up in the late few years of Nietzsche's life when he was living with and being cared for by his sister. And he just seems to latch himself onto Nietzsche's train and even is hired by his sister. Steiner's goal was to take over the spiritual-philosophical trend in Germany and push all the actual spiritual knowledge and Paganism out of it and replace with a Judeo-Christian narrative and pass this off for "western" tradition. This is why the Thule Society denounced him as Steiner was also actively attempting to organize the Theosophical groups in Germany to oppose National Socialism and the Thule Society. Steiner used psychic warfare against them and got into a magical war with Thule and he lost. Steiner was known to be an agent of the Jews.

Nietzsche due to his way of living spent most of his time in quiet places in solitude this opens up the mind psychically he even called his work meditations he had some type of discipline even appearing in a mundane practice. From studying his life I wonder how much of Nietzsche work was actually channelled without him knowing such. Tesla was the same and Hitler was an open medium who channelled some of his speeches and works as well but he did so knowingly as highly ascended being who had a life time of spiritual practice dealing with Kundalini energy and development of the mind.