Hello @JulianMill thank you forreplying to us and trying this step.
These graphical issues could be caused by a number of things. To help narrow the cause down, could you please run through all the steps in this guide >
https://www.ubisoft.com/help?article=000061047
Should none of the steps work for you, I invite you to create a support case with us and upload your system files to your case, so we can continue this investigation and take a look at any hardware or software or drivers that could be causing this.
You can contact us using this link > https://www.ubisoft.com/help/contact
If you can send us the following files, that would help us to look into what may be causing this graphical issue >
Creating a Dxdiag file > https://ubi.li/msrxL
Creating a Msinfo file > https://ubi.li/lmiCE