Usually the app should be fully prepared before the promotion of the app, and warm up before going online. You can lay out news sources from the community, shops, industry articles, and PR websites to prepare users for the early cold start in advance.
Before the app is put on the shelf, it should be laid out in advance to optimize the content of all aspects, including: art materials, descriptions, etc.
When the product is on the shelf, the Apple store has a weighting of 1-2 weeks of new products. It is recommended that Apple ad placement, information flow, and video advertising be purchased within the budget at this time, and strive to make the product weight when it is on the shelf.
If you wait until the basic optimization is completed before placing ads, you have missed the early store protection period, which is not very beneficial to developers.