There is a process from the products being sent from China to the Amazon warehouse to being put on the shelves for sale. It is not done in one step. After the Amazon warehouse receives your goods, it will enter the pre-sale status. Amazon will give an estimated shelf date (the In Stock on xxx you see at the front desk), which is almost the shelf date.

As for the time from warehousing to shelf, there is no fixed standard, only a range, generally within 1-3 weeks. If it has not been put on the shelves for more than 3 weeks, you can open a case to consult Amazon customer service and ask them to help check the progress and see if there are any abnormal problems and follow up in time.