Anecdotal, but I have to say I think many of the applications of force touch / 3D Touch are pretty bad.
The worst case is when you have both long press and force touch actions on the same element. It quickly becomes difficult to get the one you want.
This is the case on the iOS home screen (Springboard), where trying to switch to icon move mode becomes difficult. The same applies to links in Safari, when you try to get to “contextual menu” (open in a new tab etc.).
It seems things have improved over time (not sure if it’s due to newer phones being better at it or if I finally mastered the difference between the two?), but I still feel it’s an overload of two similar gestures.
With Apple now removing 3D Touch from the iPhone XR and switching to “Haptic touch” which seems to be a different form of overload, I really feel this hasn’t quite delivered on its promises. The only 3D Touch feature I actually use is the keyboard trackpad mode.
Also remember that not all devices implement it, so you may end up with different user experiences on different devices, especially if your app is used alternatively on iPhone and iPad.