Primarily I linked his life explained video series, but he also is a book author and has a primary website about him: https://www.hanswilhelm.com/
It looks to be mainstream esoteric stuff, but I really liked the videos and the guy seems to have some deep insight into mysticism and spirituality. I categorised it as esoteric, but it is not that detached from reality than it is common in the scene, but in the end it is still very esoteric, no idea if normies will be able to understand it. Even if you don't believe in all that stuff, there are still nice lessons to learm from the videos.
I think I watched all his videos, so I can recommend them, the books however I have no idea, I don't buy that many physical books, they seem to be primarily childrens books anyway, but it is probably interesting to see how someone who knows about mysticism writes children books as children are usually more susceptible towards mysticism.