I’ve owned half a dozen iPad models, and many LCD iPhones. This problem is a completely different LCD pressure issue, which is indeed unique to the iPad mini 6. I can very lightly push anywhere on the display and the focused pressure points that react are nowhere near my finger — all are along the top and bottom edge in portrait orientation. It suggests that the underlying hardware (speakers, buttons, camera, screws, etc.) are pressing against the screen more than they should.
Apple is now replacing my iPad mini 6 due to this issue, but I suspect the replacement could have the same problem since all of the demo mini 6 models in the Apple Store had the same issue (NONE of the other iPad models did), and because many people’s mini 6 replacements still have the problem. This will likely remain unsolved until Apple either revises the design/production slightly or a new mini 7 is released.
If anyone is considering an iPad mini 6 purchase, definitely handle one in-person first to make your decision about the screen quality and how it might affect your use.