I think the feature got more confusing as Apple started to phase it out. They dropped the feature where you could force-touch to select text (on e.g. a web page rather than typing) and press harder again to select eg sentences/paragraphs. They also made force touch and long press do the same thing in many cases. I think about the only place it works well is in the keyboard but sadly there are now a bunch of bugs there with replacements/corrections not interacting with the text suggestions properly (and they deleted the feature where pressing shift while replacing will capitalise/uppercase the suggested replacement)
The one thing I remember was buying the phone when the model was like 6 months since launch, pressing on an app icon on the desktop and randomly getting either the 'move the apps' state or the context menu with apparently no logic to it.
And nothing's changed since then. Sorry. It's too confusing.
