Wow, I think this thread so far reflects more the INTP/ENTP dynamic than the ENXP OP question. I'm just waiting for the thread to get moved.
On the surface, ENTP and ENFP look the same *to outsiders*. ENTPs and ENFPs IRL can tell each other apart.
But the real difference is about what goes on inside, how you process and filter reality, etc.
You think you don't care about things -- is this because there are blockages and you aren't letting yourself be vulnerable and feel these things?
Everyone has a 'natural' or 'most healthy' or 'most functional' level of emotionality - sensitivity, receptivity, expressiveness, etc.
It's not unusual for ENFPs or other 'F' types to have a period where they feel hard or cold or more detached. Especially as safety or recovery mechanisms. It is in fact, because you are so sensitive that you take things harder and have to shut off or let go.
I think the difference between and ENFP and ENTP or really any 'F' vs 'T' is that this makes the F miserable. Whereas if detachment and stoicism etc. is *natural* for you, you won't feel miserable. Hopefully?
Ask why not what. That's your best bet for figuring this all out.