PACKAGE DISABLER NO ROOT -great solution
I am still unrooted, since I need knox, and my computers run linux only, so it was difficult to block/hide apps by using the software by Gatesjunior which this thread itself suggests.
So I googled a little bit and I discovered that the command 'adb pm hide package name' allows to silently disable the chosen app, but still I am on linux and adb via usb does not work (maybe there is a little chance via wifi even without root, but I am not sure).
So I tried with terminal emulator and saw that the command is there, but does not work, since it requires the permission to manage the single users and, since permissions in android must be necessarily declared/required with the manifest xml file, there was no straight way to add that permission for an already installed app (I mean the terminal emulator).
So I was going to download the latest apk tool in order to hack the manifest of terminal emulator and add such permissions, when I saw this app
https://play.google.com/store/apps/details?id=com.ospolice.packagedisabler which isn't well known, but does the exact thing I was looking for.. It silently disables any app just like the windows software by Gatesjunior. The standard version has some limits (e.g. you can disable only a certain number of apps) while the paid one is a bit more powerful.
I bought the latter, mainly to support the dev.