I just took a shot from a trip to the Czech Republic this summer, and from that shot I only the skies overlooking a large lake, to represent the range of blue that can be captured without exaggerated color saturation, simply as a basis of comparison to OP before and after. The wide AOV afforded a good representation of how the blue saturation varies across the sky, even without a CPL in front of the lens!
So to me your lastest post exhibits no so much 'oversaturation' as much as a somewhat 'unnatural hue'...the shot I posted are like skies I see at home in CA or most anywhere else in the world I have been to.
I agree with PhotoGuys about Contrast. One can see that the second image has lost detail, which was present in the OP photo...from the front of the building to the rider's right, above the red stripe area. This shows the difference, original vs. later post...
Even the OP photo had plenty of contrast and even a bit too much. Perhaps you need to tweek the Contrast setting on your monitor to make the monitor more contrasty.