I know this post is 2 years old but here
Witcher 3 Debug console
Windows Key + R
Type in %appdata% and press Enter
C:\Program Files (x86)\Steam\steamapps\common\The Witcher 3\bin\config\base
Click on general
On the bottom underneath the text already on the notepad put in
DBGConsoleOn=true
By this point the general should look like this
[General]
ConfigVersion=2
DBGConsoleOn=true
At the top of the notepad window click file and save
Congrats you now have the debug console enabled now in game if you press ` or the key to the left of 1 you will be able to open the debug console from there you can type in removeitem(item command name)
I would also like to direct you to this link
https://steamcommunity.com/sharedfiles/filedetails/?id=765050564
which has all the information you require and need for the debug console