I’ve been using iPhone 6S since it was the flagship and I still don’t know any 3D Touch operations or shortcuts. I actually had to look up just now to double-check that this phone even has it and it isn’t disabled. I’m sure I could find a cheat sheet if I cared but generally I think of “intuitive” as being something you’d discover naturally at least once in nearly 7 years of daily use.

I'd been using iPhones without that feature since 2008, and there was really no reason for me to assume there was a fundamental change. Everything else was basically the same until I tried to delete some apps.

I suppose if my first iPhone was one that had this functionality, maybe I would have figured it out.