If you put the NF version of the Moltke next to the Deutschland you will see that it is
just a Deutschland with 4 main gun mounts instead of 2, a couple more secondary
mounts and increased displacement.

So yes, it is not entirely fictional as it is based on the Deutschland.
But it has nothing to do with the WW1 Moltke, they just share the same name.

video games are not real, thus they do not have to be realistic in any way, shape or
form.

they have the same size guns, near same secondary armament capabilities, dont think it is
entirely fictional

The ingame Moltke and the WW1 Moltke are not the same ship.
The ingame version is fictional.