Look for versions that explicitly mention the "Rape of Christ" or "The Bone" (masturbation) scenes, which were notoriously cut from the original theatrical releases. Quality Disclaimer: Many of the "uncut" versions on the Internet Archive
Watch this breakdown of the ongoing censorship struggles and why the full uncut version remains elusive on standard platforms: Kermode Uncut: What To Do About The Devils kermodeandmayo YouTube• Dec 16, 2014 the devils 1971 internet archive
This official suppression has created a void that the has stepped in to fill. The Archive hosts multiple user‑uploaded versions of The Devils, most notably an upload titled “The Devils (1971) Extended Version,” described by its uploader as a “fan edit that uses the British theatrical version, which is more complete than the heavily censored U.S. theatrical version, and restores two infamous deleted scenes first glimpsed in a BBC documentary on the film from the early 2000s, which Warner has forbidden from being aired since then”. The uploader adds: “Warner is doing their best to bury this film. So. In spite of that. Here is Ken Russell’s terrific tour de‑force”. Look for versions that explicitly mention the "Rape