A big thank you to all of you. It is fully working now.
The maps not being visible was due a missing / in the Excel formula.
...now I only need to manage to convince XnConvert to not double the .dds size...
Edit:
For anyone trying to do something similar:
TexConv got used to compress .dds files.
(use Max Compress and BT1_UNIFORM)
To get the full filepath list I used DirPrintOK, exported a .txt and used Notepad++ to fix the list so it could get used in Excel (LibreCalc).
The mod is now fully functional and including all available maps. Behavior: When you first open up a large map you notice it load (very quickly). There is no visible loading time when reopening a map.
The maps got optimized for "
Yet Another ReShade Preset" (which is great btw) after changing the following settings:
[FakeHDR.fx]
HDRPower=1.035000
radius1=0.906000
radius2=0.880000
[Colourfulness.fx]
colourfulness=0.067000
lim_luma=0.702000
enable_dither=0
col_noise=1
backbuffer_bits=8.000000
[Tonemap.fx] fog color to FogColor=0.027451,0.027451,0.027451
Thanks again for all the help