After upgrading to iOS 15 I can no longer maintain a connection to wireless internet

After upgrading to iOS 15 I can no longer maintain a connection to wireless internet on my iPad Mini (5th Generation). I have done everything to removing the network and reinstalling, and many other steps including attempting to utilize iTunes. All my other devices, both wired and wireless, work (e.g. iPhone 11 with same iOS update, my wired computer, my wireless laptop). I have contacted my service provider - modem has no issues. so all it can be is the update performed. Please help!!! Thanks so much!