I agree with the comment above.
You could try to add an alpine shader (for example), still restrict it by distance, but make it along the whole horizon.
With the proper distance shader settings there will also be a kind of a build-up for the heighth of the alpines.
The water transparency could be better indeed, though I don't find it really disturbing.
The tower looks amazing. I really like it. Great displacements and good shading as well.
Atmo and lighting are just fine. So in overall I think this is good work.
Looking forward to see your update
Martin