Not an expert but this sounds like a behavioral school of thought. It’s a strong statement that there are no psychological truths across cultures. Can you recommend a source where I can learn more about that?
Shouldn’t at least psychoanalysts be able to work across cultures?
But even if knowledge of a culture is needed, there is still the possibility to learn it. Additionally, a view from outside could also be an advantage. Other cultures can have answers to our problems.