As everyone knows, the optimization of Gothic 3 really sucks.
We're all trying to find the optimal settings to push PCs to their limits.
I'll demonstrate below that it only takes a few steps to make that game playable, as much as possible.

• Install the game on SSD, not HDD!
  The difference is really huge! It's about +- 50fps!
  
• Install the Community Patch v1.75 (1.48 GB)
  https://www.worldofgothic.de/dl/download_478.htm
  
• Install the Update Pack v1.75 (28.54 MB)
  https://www.worldofgothic.de/dl/download_523.htm
  
• Install the Parallel Universe Patch (3.13 MB)
  https://www.worldofgothic.de/dl/download_678.htm
  
• Set up your own video settings!

In case the link doesn't work, use the links below!
Copy it and paste it into a new tab, as Steam cuts the links with the link filter for some reason.

Community Patch v1.75
https://www.worldofgothic.de/download.php?id=1283
Update Pack v1.75
https://www.worldofgothic.de/download.php?id=1371
Parallel Universe Patch
https://www.worldofgothic.de/download.php?id=1663

Check out the screenshot. At the bottom of the settings, there is a separate category for options that cause performance drops. Most of these options are pointless and only result in problems. It's essential to turn them off!

The game's performance IS NOT significantly impacted by the Overflow effect option.
It's up to you what to do since it also improves the game's beauty and vibrant colors.

The default configuration significantly restricts the rendering range.
Below is an example of how my ready-made file significantly improves the range of world rendering. It's clear that the ge3.ini decreases FPS, but with today's powerful PCs, this shouldn't be an issue.

ge3 [drive.google.com]
Copy and paste it into the main directory - \SteamLibrary\steamapps\common\Gothic 3\Ini

It includes a modified version that changes the field of view and increases the number of CPU threads. If you forget to create a backup, there's also a default version inside.

• Custom ReShade for Gothic 3
  
  https://steamproxy.net/sharedfiles/filedetails/?id=2888610051
  
  One of the fundamental improvements is ReShade option. It significantly improves the quality of graphics, making the game more colorful and vibrant.
  
  The installation is incredibly simple. Just download the ready-made files and put them into the main game folder. There's no need for any manual installation! The shaders are loaded automatically when you launch the game.
  
  HOME key, as I remember it, opens ReShade's settings (in-game).
  
  ReShade [drive.google.com]
  
  Created by Tore Andersen.
  
  
  
  
• 4GB Patch
  
  A patch that expands the in-game memory from 2GB to 4GB. Thanks to the 4GB patch, the game shouldn't crash to desktop. It's not a good idea to using only 2GB of memory in today's times with current hardware. It can only be used with a 64-bit system.
  
  To install: Unpack the file an run it. Select "Gothic3.exe", and click OK. Once you get a message saying 'Patch successfully applied', you're done.
  
  4GB Patch [ntcore.com]
  
  
  
• Mouse Fix
  
  Community Patch v1.75 can solve the entire problem if the mouse is not working at all. However, what if we have a problem with mouse sensitivity? To fix that, simply launch the game and go to Settings, then click on Mouse Control. Set the X/Y Sensitivity with a 45% difference and lower the Smoothing to -98%. This will restore normal controls.

There are only a few steps to a significant improvement in the quality of the gameplay.
This affects not just the smoothness of gameplay but also the visibility or graphical enhancement.
I promise it will work for you!

Special thanks goes to PeTak for help.