Let's see if I can help since I have been down this road recently.
First, is Fe in the service of Ni or Ni is in the service of Fe? It is hard to tell sometimes, but there is a difference.
Fe as dom is more active, quicker, a doer. Ni as dom is slow reacting, deeper, more detached.
For me, I am an instant response guy. And Ni can be fast, but with Fe in co-pilot mode, decisions come slower, because decisions are made by Fe, not Ni.
Next, Ti vs Se. According to some theorists, the inf function actually rears its head before the tert, because it is connected to the Dom. So Fe with Ti and Ni with Se. There is a struggle in young adulthood between the two. When we get too anxious and stressed, we turn to our inferior function, aka, being in the grip.
Being in the grip is very different between ENFJs and INFJs. ENFJs get trapped in the abyss of inferior Ti, a dark negative place much like severe depression but not quite. INFJs get into Se extremes, including suddenly making frivolous purchases and wanting luxuries.
A much more in depth look into ENFJs in the grip is
here.
Here is the INFJ one.
I really found looking at these very helpful.
I thought I was an introvert.... but it doesn't fit me cognitively.... or socially, really...