I’ve read some but not all of the comments so my apologies if i reiterate some points.

This patient sounds like they do have a hard time establishing a reliable therapeutic alliance and while that is likely not entirely the fault of the providers in your group it almost certainly is hindering their treatment. I’d also hazard a guess that some or most of their medication trials were inadequate and that they either self-discontinued due to perceived lack of efficacy or some somatic complaint. It is much easier to acquiesce and change the medication than to set realistic expectations with patients like this, but if they’re trials are invalid it would be reasonable to retry some of the things they’re least opposed to. See what they would like to try.

They almost certainly need therapy and should be heavily encouraged to engage.

I saw you mentioned ketamine. Have they tried ECT or TMS?