I guess I can see it

Kinda

Similar but different.

The issue is hair styles - the Stranger Things hairdressers have been trying very hard (and doing a very good job) to copy the hair styles that were in fashion in the mid-1980'.s

Ferris Bueller's Day Off is set in the mid-1980s.

One would, therefore, expect to see the same or similar hair styles.

I see your point, but I also feel like you're thinking it is only the hair where I see the similarities (correct me if I am wrong pls).

To me, the two are so similar in general that I actually accidentally called Jeanie 'Robin' a few times.