I recently purchased a Note8 and had challenges with the screen as well, especially after adding a screen protector. I've read and researched most responses. Changing the navigation bar in settings is not the solution. It is specifically for the Home button.
I found an app in Google play store called Touchscreen Repair. I no longer want to throw my phone or return it. It is not as seamless as my Note4 but it is definitely 110% better and faster than 2 days ago. No more multiple taps on the screen anymore to open apps or on the keyboard.
FYI - I have a Zagg Glass Curve screen protector
I wanted to offer another possible fix...tried the ones here for touchscreen calibration with little success. I recently bought a Note 8 and ordered a number of different cases. Many of the thicker ones with the better bezel protection affected the touchscreen under the generic curved glass full screen coverage protector I use - the ones that worked best are the thinner TPU cases that don't wrap quite as tightly around the edges - my guess is many of those slightly lift the glass which affects the touchscreen underneath - the problems are worst near the sides. I have zero fondness for curved screens, but my LG V30+ has one and never had an issue like the Note 8.
Here's a case I found with a magnetic plate and kickstand that doesn't affect my touchscreen, as an example - https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F142894449211
Exact issue I've been having with Zagg Tempered Glass Protector. I tried the app you recommended but still having issues especially when using Swype. The screen was super sensitive without the protector. I might have to get rid of it and hope my folio case is enough protection.
SORRY BUT THIS APP IS NOT THE SNSWER JUST A PATCH, MORE DRAIN ON BATTERY, APP ISN'T NEEDED. The setting is not named what you would think it should be, like touch sensativity etc...TO FIND SETTING Go to:
settings-display-navigation bar-hard press home button....Turn off.....Problem solved phone will respond fast & easy taps!
I have never had a screen protector on my note 8 and there is places i cant click or submit i have to keep tapping if i cant move it to the top of the phone that is the the only place it allows me to click cant wait for note 10!!!!