Doesn't help me, sadly.

This reminded me, though, that I had forgotten to post a little oddity I had found out: When I start the game via the desktop icon instead of the play button, the intro scene doesn't behave any differently, but instead of with a black screen it is followed by the Thronebreaker logo animation and then the main menu. However, other than finally being able to set the text language to English this didn't really help any, as when I start the game proper, all I get is a black screen to the sounds of chirping birds and a bubbling creek.

Your text is hard to understand. It makes little sense to me.
If it means, you cannot play, because you do not see anything:

As there is still no patch out:

You could try to change the monitor. As at the moment, the second monitor is used as a base setting, activate your mainboard grafic card (also called "onboard" grafic card). just google, how to do this.

Then put the monitor cable for the connection to the grafic card to the onboard grafic card.
I have installed my second monitor the same way and my game started there. I then activated the windows mode and put the game on the first monitor, where i activated the full screen again. Since that time i had never any problems to start it again.

It will do not help you

I lowered the screen resolution 1 level (1920x1080 to 1600x900) and disabled full screen, and the movies now load.

Oh thank god, lowering the resolution to 1600x900 worked for me, didn't even have to disable fullscreen. Everything looks ugly, but at least I can finish the game without missing the cutscenes.

Thanks for the tip!