gmay3, thank you for all the advice. I understood the 3D printing is not easy from day one, in fact I welcome the challenge

The problem with sticking to the glass is that it's something entirely new. I've printed quite a few things with PLA (bad quality, but still), and never ever I had any problems with adhesion even without using hairspray. In this case it looks like the print is shrinking into the center when it cools down. Maybe it's because it is 100% infill. Will be tinkering around some more today.