I don’t have any on hand, but there are plenty of references online for trying to deradicalise cult members, and many of the factors in play here are similar, so those skills can be used to try and open these people to other ideas.

This could have some, I haven’t checked in depth: https://www.reddit.com/r/QAnonCasualties/wiki/resources/ (if you’re not already familiar with QAnon conspiracies, Wikipedia article)

An important thing is to not aim for immediate change of mind, but to empower them with an alternative framework which is ready for them to consider when they face a contradiction in their worldview and the world.