There's a difference between being mentored and having the mentoring character essentially be a co-protagonist.
In the very first Raimi Spider-Man movie, Peter DOES get mentored, in a way: uncle Ben's "with great power comes great responsibility" is arguably the best 10 seconds of mentoring in pretty much any superhero movie. But that's all it is. 10 seconds (might not be literally 10, but it's a ballpark figure; using it to illustrate a point here, no need to take me to an international court of law if it's not exactly 10
). Then the rest of not just the movie, but the TRILOGY, Peter is pretty much on his own.
Compare that with:
- Overt mentoring from Stark in Homecoming, with A LOT of Stark screentime. I mean, you can tell, not only is Stark in the promotional poster, so is Iron Man!
- I would argue this much screentime was unnecessary because a mentoring relationship between these characters had already been established in the third Captain America movie.
- The primary villain of Homecoming becomes a villain due to the actions of Stark and others. Was this the case in the comics? Vulture seems like a good villain and was honestly played brilliantly by Michael Keaton.
- The primary villain of No Way Home becomes a villain due to the actions of Stark, in a movie where all the technology is Stark-provided and Stark's presence looms heavily in almost every aspect.
I wouldn't call this "standing on his own." In fact, while writing my response I started thinking, "man, are these Spider-Man movies, or Iron Man movies?"
Being a bit facetious, but yeah, there's a difference between occasionally reminding audiences that there's a shared universe, and depending so heavily on that shared universe in your individual hero's movie, that you start compromising the identity of your individual hero that you're supposed to be focusing on.