I'm gonna address this according to the function theory, because like most people I think after researching the functions you come to understand that MBTI is like a simplified theory that bases itselfs on the functions but saves you from the important details to truly understand people and personalities and instead provides you with general descriptions you can use on literally every person. The big stereotypes come from it, people who don't understand typology, psychology and don't respect it thrive on it because it is so fun and easy to put people into the most general catagories so we won't need to go through the process of actually understanding a person. Even if you learn the functions you'll understand that they are only a small skeleton frame (that also changes with time) and how each person exists in it varies quite differently and to truly understand a person you'll have to do the crazy thing of TALKING with them, BEING with them and then maybe finally feelers will stop "feeling" that thinkers don't have feelings and thinkers will stop "thinking" that feelers don't think.
Now about the difference between N/S, well first of all not only do I think there's a big difference between Ni/Ne and Si/Se I also think that there's a big difference between Ni & Ne and between Si & Se themselves. Let's take the stereotypes we give to each function and understand where it's coming from and reveal it in a more correct manner:
Ni - Can predict the future.
Ne - Creative, thinks out of the box.
Si - Sticks to traditions, can't think out of the box.
Se - Shallow, impulsive, Chad & Ashley.
Ni: What Ni does the way I see it is focus on ONE thing at a time but sees as many angles and other things connected to it as possible, this leads to being able to come up with a lot of scenerios and possibilities regarding anything, while Ni is very centerd around TRYING to predict the future, it doesn't mean at all that it can do it all the time correctly, actually it is wrong most of the time. The secret that Ni dom users don't tell you as to why it seems like they're always right and can "predict" the future is that WE DON'T CLAIM WHAT WE DON'T KNOW. We are dead scared of the unknown, we don't think about what we don't know, and we don't try to predict what we know we can't. Ni likes to understand anything to the core as much as possible, so it will mostly try to avoid taking a stance or an opinion about anything that they don't know enough about. I think the stereotype comes from how the Ni is constantly asking: "What will happen?" so yeah of course they'd be good at speculating about the future, they're constantly busy with it. No one talks about the suffering that they exprience from it though.
Ne: Well according to our society, thinking about as many ideas that are original or at least ideas that aren't being thought much about is called creativity. Whether you agree with that or not, that's what most people think that creativity is. People who can brainstorm are seen as creative, people who say things most people don't say are seen as creative etc. The Ne function focuses on a similar question to Ni but actually quite different which is: "What could happen?", Ne doesn't like to focus on one idea and it's many angles but jump from one idea to another, creating a wide spectrum of ideas. So yeah, according to society Ne doms are creative. But calling Ne just creative is insulting it, any perceiving function can generate ideas and theories, Ne just tends to do it more freely.
Si: I'll be honest this function is hard for me to understand, but the way I see it the stereotype is half-right. Si is focused on familiarity which makes them seem as closed-minded, can't think out of the box and sticks to traditions. If i understand it correctly Si users start this way but come to realize like most people that they don't like something about the world, and so they go on a quest of trying to beat their fears and using their inferior Ne to pave a path into life that will give them the security and stracture they look for but a stracture that doesn't make them suffer. It might be hard to crack through Si's tough shell, but let me tell you that they deffently have their unique opinions, and they become an unstoppable weapon when they can manifest on their new ideas and manage to implemant them into a realistic and well planned system.
Se: Se is focused on the concrete objects and the world infront of it, this is where the shallow stereotype comes from. There's nothing, absolutley nothing shallow about being able to connect to life in the most genuine way. All the brainwashed N users will say that Se doms are shallow, don't think, don't respect life's deep meaning, when in reality those N users are dying to be able to exprience what Se doms exprience. That "deep" thing is a source to so much suffering, depression, anxiety and ultimatley suicide. Se is not only deep but it is also extreamly smart and truthful to life. The stereotype comes because Se likes less to focus on connections and underlying meaning, but it's a key word: "underlying", because it deffently focus on the meaning that is right there infront of all of us, which many people can't see (including myself) and won't see for the entirety of their lives.
I'd like to sum it up with mentioning that everyone need to remember that INFJs USE Se and have it. and ESTPs USE Ni and have it. All the types use N, S, T & F. Our role as a person is to go deeper into the function stack and learn to correctly control all of our functions, so for example if you ask me, the INFJ becomes the "deepest" (god I hate that word) when it can be fine with not being deep at all.
I hope I helped anyone understand something, and if there's anything you'd like to fix or add please do because I rumbled for quite some time and may have lost my mind a little while writing this
