Coincidentally, I am also from a 10 million country surrounded by mountains... and I feel the need to say a few words.
What sovereignty are you talking about? The one we had before WW2, right before we were occupied by Germans? Or after WW2, that brief moment before we were controlled and later even occupied by Russians? That sovereignty is an illusion, especially in today's interconnected world. We can either be small and be controlled by the big ones or be a small part of a big one. Is EU perfect? Certainly not. We can talk about reforms. But despite all shortcomings, I would still say that being part of the EU is the best era of our history.
And saying that people had more say over our country during the communist regime than we have today... that contradicts my experience and this is the sentiment I would like to express in the strongest possible terms.
And I would not be so sure about what "most people here would rather..." - if I might share my position on this: I voted yes to join the EU in order to get roughly what I got and I would not change my vote.
Just my $0.02 - article 13 is not about what Germans and French want, it is about what powerful lobbies want - being outside of EU would not save us from something like that despite what majority of the country wants - the fact is that we were not overruled; check the stances of our representatives (https://saveyourinternet.eu/cz) - unless there is some other mountains-surrounded country I do not know about, most of our MEPs voted for the article 13.