iphone IOS 15 ,is not able to open wifi or bluetooth

Well, as you chose your own answer as best answer you probably know the reason, but anyway, it means that the radio chip in the phone that enables both Bluetooth and Wi-Fi has failed, so it’s time to get a new phone. The cost of a repair would not be a good investment.

What model iPhone?

Sorry to be the bearer of bad tidings. There are a few 3rd party shops that can replace the chip for less than Apple will charge, but it is a pretty old phone and something else may fail.