Yesterday I wanted to play Humankind with a buddy, we already had a safegame, everything has been loaded so far, but as soon as we get to the shop screen, after 10 seconds it says "You have lost your internet connection. How can I fix this problem?"

We got that problem sometimes too.
And often the game bugs for example a fight so that we have to reaload the game.
I would say that we reload the game ~6-10 times a session of 2~6hours