I use Platforms->windows->package project, I got “shipping” build configuration chosen.
I still get prints in the game.
What’s wrong?
I read some older threads that people try to package project through project launcher and that works, but that’s not the way it should work and there are options that could make mistakes.
Is there any way to fix that?
See my answer here
I used project launcher, wasn’t that hard, followed some tutorials on youtube and it works. I hope nothing breaks.
But it got rid of the messages, right? 
yes
When you click platforms drop-down at the top of the editor, are you picking “Use Project Settings” or “Shipping” ? try choosing Shipping
sure I’m using shipping. It doesn’t work, it builds development version.