Psychologist here (though not a forensic one, which might be more helpful) but finding myself loathe to give an opinion without knowing more facts.
That said, listening to TWS there was quite a lot about her childhood and family which, if true, could be helpful in understanding all this.
I wonder which of her early emotional needs were met and which unmet? That would be my starting point.
Where did the sense of insecurity - and need for “more” (Attention? Validation? Approval? Sense of importance?) start?
What did her first relationships teach her about honesty, integrity and morality? About getting along with others and playing by the rules?
Early relationships are crucial but the problem is knowing what to believe from the information she’s given.
Was she really silenced, neglected and sometimes ridiculed by her parents in the way she describes, for example?
And as others have said, is the pathological lying and stealing HER issue or tied up with the relationship with TimMoth?
There’s so much we now know but still so much we don’t know.
Sorry - I was one of the original psychology correspondents but I feel I’ve failed in my work! No fudge for me….Maybe one of the others will give a better answer 😊