Super typical of people like that. The triangulation especially. In psychology I think it's often used literally but I think a broader definition to include bringing in new people to a situation to try and maintain control and "win" since they're almost never discussing anything in good faith, makes sense.

https://psychcentral.com/blog/psychology-self/2019/10/triangulation-and-narcissism#:~:text=What%20Is%20Triangulation?,individuals%20except%20through%20the%20manipulator.