ehy mate, we all appreciate your effort for helping all of us, but that pinned post sometimes is useless, even if you scrupulously follow the rules, guides and recommendations. I published my demo 2 weeks ago and it's still unlisted. It will take 3 minutes or it will take 3 months, it really depends on randomness. And you'll end up right here to see if other devs are experiencing the same issue :)
The gist is, that unlike in video games there is no loading bar that shows the progress and no notification either way, if or when your game gets indexed.
It is frustrating. Calling them rules and guidelines kinda implies that, if you follow them, your game will get indexed. But you do not know after several weeks, if you are still in the waiting queue or if it was decided to not index your game. Or if it was decided to not inspect it at all. It is a black box.
But I can tell you that 12 days is nothing. You should worry after 40 days or so. My personal guess is, that the queue is not fifo and it just piles up seasonal or for other reasons. Checking for indexing just has low priority, compared to other issues. Also, because Itch's stance is, that you should not depend on indexing and market your game independent from being indexed.
The sad truth is, even with being indexed, most devs are lucky to get a dozen views, let alone a review or comment.