You can simply create mipmaps for the texture and then extract x69 (the desired size), or, if you really need a larger image size, as shown in the second screenshot, you can add Scaling to BackgroundSimpleTexture.
I've attached your mod with this fix.
Okay, I understand the first point; I managed to get it working! The second point is also clear, but I need to process and test it... I'll write here later. Thanks, that's great!
P.S.: I wanted to increase the size of the side tabs of the book, but it didn't work. Could you please demonstrate a specific example with the archive above, for example, with the second tab in the hero viewing mode? (the bag icon, equipment) Bookmark2_Active.(Texture).dds