According to my observation, after the end of the sale, it takes at least one or two months, sometimes it takes more time, if you choose by quality, I think it may be longer, but as a result listing on a good exchange.
Listing on decentralized exchanges can happen automatically and free of charge immediately after paying the token to investors.
Listing on centralized exchanges depends on the amount of money collected by developers and on their desire. The more money the developers have collected, the more chances that the token will be found on a good stock exchange.