So I've sent itch.io an email asking about the situation and what to do. They do have a link (this one: https://itch.io/docs/buying/already-bought) where you can see how to get the steam key and the solutions for it. They didn't answered yet (tho they do say that itch.io doesn't solve problems for specific creators or something like that).
The key is still nowhere to be found, but I guess I'll wait and see if they do answer and provide a solution.
Hmmm... I just checked and it's still not there. The guide said the exact same thing as the other one. It should be right beloy the "regular" downloads. But somehow, there's nothing, just the download instructions and the community.Anyways, this is what you see when you purchase it:
When I got the game, I think that the purchase said I'd get a steam key too, but I can seem to find it. I tried to follow the instructions too, am I missing something?