Indexing or lack thereof does not affect promotion.

Unless you promote for people to search for your game or username instead of a link to your game.

you have to wait till your game be ready to be indexed

You don't. It was bad luck. Most games get indexed by automatic. Itch will not tell you why your game was picked for a random human inspection. But as it is with humans, all sorts of things can happen to cause a delay. My personal theory is, that they got hit by one desaster after the other without time for recovery. There were some bad ddos attacks in the past months, some server hickups and other things. Also it is winter and a lot of people are sick.