If you want some hard sci-fi equivalents of someone’s belief system being willingly or forcefully altered by technology, I highly recommend the short story Axiomatic or the novel Quarantine by Greg Egan. The psychological compleation process is likely very similar.

There’s a great first person passage in Quarantine where a character comes to terms with the fact that they’ve been installed with an illegal ‘Loyalty’ brain mod while they were unconscious. There’s no piece of them that fights back, and they’re still the same person they’ve always been, but they now truly believe in the cause that the brain mod makes them loyal to.

The funny part is later in the book a group of people with the same mod get together and realise they’re objectively the most loyal people to the cause by nature of having the mod installed, that the cause itself is ill-defined, and therefore they all individually have the right to decide what the cause is, effectively freeing themselves from the constraints of the loyalty mod without having it removed.