I'm wearing two socks and both are quite thick. I still have this odd feeling, as if I was wearing fins... and also my foot sometimes slides forward. In my previous shoes I was getting my toes jammed, now I feel like my toes are floating and have too much space

I have ordered a thicker insole, as the original one is quite thin. Maybe this will improve my feel. I am also considering going down another half size, but I am afraid they will be too small. I'm a little obsessive about this, I cannot play comfortably if my shoes feel odd, I keep thinking about them
So have I understood correctly that you have ZVC4 size 10? Could you measure the insole?