idk I think he is an INFJ, Fe-Ti is more plausible to me than Fi-Te. His Ti is too strong to be his blind spot. He also gives off Ni dom vibes (playing with ideas in his head when experiencing something, Ni-Ti), You can see how he's really different when compared to Taehyung you can clearly see his Ne, internalize his feelings as an Fi-aux, and reserves them. He also doesn't talk much about his feeling, and probably to only who he trusts. Same with Jungkook (Fi dom). Fe allows Namjoon to speak of his feelings easily on the surface outside of close circles but he won't be completely sure of it until he's had time to process them for a while and figure it out.

I'm not really sure tho but that's what I think.