Richard Rohr, Andreas Ebert, and the Enneagram

For what it's worth:

• Huggins, Ronald V. "The Enneagram’s False History and Occult Roots." Bibliotheca sacra 179, no. 714 (2022): 146–162.
• Cusack, Carole M. "Ṣūfism and the Gurdjieff 'Work': A Contested Relationship." In Handbook of Islamic Sects and Movements, edited by Carole M. Cusack and Muhammad Afzal Upal. Brill, 2021.
• etc. (I stopped here, though there is more to be found).