Nothing can open your bl_ody console? Try this.
Just like you, mate, I tried:
(Step 1: go to your \Steam\steamapps\common\Gothic 3\Ini and in the file ge3.INI change TestMode=false -> TestMode=true)
For many players, this step is enough to see and use the console in the game by pressing tilde (~).
_compiledImage and _Intern
(Step 2: go to \Steam\steamapps\common\Gothic 3\Data and create a folder named _compiledImage inside of it, then a folder _Intern inside of _compiledImage)
This step helps if your issue is a through and through black console.
(Step 3: go to your Device Manager and check if there is something-something-Infrared in your Human Interface Devices or Keyboards. Get rid of the pesky thing.)
This step usually solves the problem for people with laptops.
Unplug the Gamepad
(External devices like gamepads sometimes interfere with proper inner workings of games, especially ones which do not support gamepads.)
Alright, now, nothing of it helped ya. You have no Caps Lock or Scroll Lock on, you patched the game back and forth, and Marvin mode works (press Ctrl + S to display some stats, if you can see them then Marvin is on). Compatibility mode with various previous OCs turns out to be a futile effort. You installed all drivers available for your keyboard, you tried remapping the tilde key (which might actually help players with keyboards where no tilde key is present).
Do not despair, let me present you a solution adapted from our German friends:
- Left Shift + Right Shift + Home
And for Germans in case they wonder, Left Shift + Right Shift + Pos1.