You are confusing marketing with distribution.
Itch is a store and distribution platform, but due to its high number of creators, the visibility of a game is very, very small.
It's been said many times, Itch is not going to promote your game. If you want to sell, you must have your own marketing plan.
Uploading a paid game to Itch without any additional promotion on your side is almost certainly a disaster.
Uploading a paid game to Steam without any additional promotion on your side is almost certainly a disaster too.