If that's my case, I believe then that many people with similar Ti/Fi/Ne/Ni/Si preferences are actually mistyped INFPs. I have met some with similar preferences.
What is the essence of INFP then...? If they're so largely analytical, what really differentiates them from INTPs? One understanding of it that I have developed is that INTPs are more "by the book," as when they compare systems, everything must line up as expected, but INFPs moreso come to form their own "subjective understandings" of a system. It's still all quite vague in my mind.
Several users have suggested that I'm Ne dom. Ne is probably the most appealing function to me, as I enjoy change, possibilities, progressive-thinking, etc. I also enjoy being the center of (positive) attention, and can lead quite well if I believe it to be the correct choice to suit the objective at the time. (Te, lead by Ne?) I do think that inferior Fe fits me quite well, as it's quite a terrifying function, but if INTPs are supposed to favor Fe over Fi, that is certainly not my case. Fi > Fe all day. I likely think that 4 is my center. But I could just as well be 5w4, 4w3, or even 3w4. Like I said, performance is actually enjoyable for me. While I do think I'm introverted in that a lot of interaction with people will ware me out and I tend to avoid going to people I don't know too well all the time, I definitely could pass as an ambivert - ENxPs being the "introverted extroverts."
Really, I could be any of the four types. First type I ever tested as was INFP. I took the test with an extremely "idealistic mindset," though I don't think my drive is necessarily towards people. I can't say I ever "make decisions based on the feelings of others." So if I could get a more concrete impression of what it means to use Fi, that would probably help a lot.
INTP vs INFP can come down to the human element. The INTP basically tries to remove it, to develop a system outside or not in relation to the human experience. It is a search for what is fundamentally logical or how things work regardless of the human experience.
The INFP is developing a system within that experience or to serve the purpose of ordering it. Hence value vs impersonal logic, and the INFP using emotions as helpful signals and INTPs being more apt to find them distracting noise.
A note - "personal" doesnt mean "individual", but it means something closer to:
-being rational, self-conscious (aware of one's own human state as the lens for reality)
- having the qualities of a person, rather than a thing or abstraction (INFP context is the former, INTP the latter).
All Feeling types are described as being more "personal" and having "personal values" (which are wrongly equated with only Fi, when all people have some individual values and Fi is not
just about the individual at all). Ordering reality in terms of value (ie significant, important, meaningful, etc, in relation to the human experience) is a Feeling type characteristic.
If Fi doesnt strongly resonate and you find Fe unappealing and you do not find your mindset dominated by the above form of reasoning and analyzing (to determine value), then why not consider NTP.
The understanding of the inferior functions is so bad, that I am not going to touch the silly idea that INTPs "use Fe" as if that makes them a "Fe type", except to say that the inferior is experienced within a person's psychology as oppositional, antagonistic and rudimentary.
As noted, this is why we can find a different function in the same orientation as our ego more appealing than our inferior (ie. an INFP finding Ti more relatable and familiar than Te).
As for enneagram, I frankly do not think NTs are 4s, save a very rare female INTJ 4w5 who may have weak auxiliary Te and who may even be a mistyped 5w4 or an INFJ that is sort of on the border of these categories. NT 5w4s can seem NFish in ways though, and 5s may actually mistake themselves for 4s more than vice versa because 5s can sometimes be described in excessively dry terms.
I DO think ENFPs can be 4s, although some still think most are mistyped 3s, 6s or 7s. I think having "incompatible" MBTI and Enneagram types is often a clue that something is off in the typing...most people are not that "special", and some combos would almost require a split personality.
Lastly, you vibe more as INTP so far (having only read a few posts), for whatever that is worth.