Radicalisation is actually very interesting and I (ashamedly) nearly succumbed to the same thing myself.
There's a really good youtuber called "Contrapoints" that attempts to deconstruct with low judgement the kind of environment an Incel lives in and what the worldview is.
Empathy is always at the root of deradicalisation, so I always plug her videos when I can.
I'm glad you enjoyed Contrapoints, but I'm going to have to deflate your recommendation somewhat.
She's a good performer, but most of the time she just beats around the bush and doesn't offer any solid conclusions about anything, which can leave you feeling unsatisfied.
She had some interesting insights into Incels because of her gender dysphoria, but those insights never led to any real sympathy for them, and she still essentially blamed them for all of their problems, and shrugged her shoulders about it by the end of the video.
Also, she's made some pretty fallacious claims, like when she said that denying being a fascist was evidence that you were a fascist. Or when you tried citing Christopher Hitchens argument in favor of protecting controversial speech to argue in favor of censorship. (I can reply with specific timestamps if you want to see).
I'm not convinced that she has deradicalized anyone, outside of a handful of teenagers that only ever posted edgy memes on 4chan that the never understood them the first place. None of the people who claim she deraticalized them can actually give concrete examples of what new information Contrapoints provided them that persuaded them to change their opinions about anything. I am certainly willing to listen when someone can. Instead, it is just vague platitudes about feelings and emotions, with zero substance or validation of facts.
She also did better when she included herself in her critiques. But over the last year or so, especially on Twitter, she has degenerated into a less ironic and more self-righteous direction, which is pretty cringe.
A weakness for the specific application you are interested in is that I don't think it works with banned or quarantined subreddits - the archived dumps probably have that, but not the main API feed
It would be extremely enlightening to follow radicalisation and communication of, say, an incel terrorist.