Prof. Robert Hahn has broad interests in the history of ancient and modern astronomy and physics, ancient technologies, the contributions of ancient Egypt and monumental architecture to early Greek philosophy and cosmology, and ancient mathematics and geometry of Egypt and Greece. Every year, he gives "Ancient Legacies" traveling seminars to Greece, Turkey, and Egypt. (https://ancientlegacies.org/)
Thales may have known the famous theorem perhaps as much as half a century before Pythagoras.
The ancient Greeks were obsessed with geometry, which may have formed the basis of their philosophical cosmology.
Pythagoras may have believed that the entire cosmos was constructed out of right triangles.