Yup what works and doesn't work depends on many factors (personality type, what people have been through in life, number of dumbasses they are currently surrounded by etc) so the outcomes can be highly unpredictable no matter what you do.

But having different tools in the toolkit and awareness of what's available makes a big difference.

So I look at NVC in that context, as one tool that falls under the 'communication strategy' category. There are many tools under many categories to build trust, respect and connection with others. At the end of the day what outcomes you produce are what matters. And many times it requires a combo of tools.