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
YOU apparently have magic powers! There is NOT A SCREEN SENSITIVITY BUTTON. In fact, it took about 5 minutes to type this with a zagg screen protector on because it screws up ALL of the touch, especially down the sides. You can argue about it all you want, but there IS NO SCREEN SENSITIVITY BUTTON SUCH AS ON NOTE 4 (for example). The ONE AND ONLY pressure change(able), is the HOME button.
You have a placebo effect working in samsungs favor
That was a tact response, but it worked THANK YOU DUDE WOOOOOOOTTT!!! I was about to loose it. Adjusting home button sensitivity is the answer. make it light... Other words make it so.!