Can I downgrade an iPhone 15 pro max to an IOS that works?

My wife’s brand new iPhone 15 Pro Max is unreliable at best and I would say unusable. The glitching in the iOS and in apps makes the phone useless for long periods of time generally requiring a hard reset. It seems to be in network connection issue, but like something I’ve never seen before where apps, including settings won’t open and the phone just shows a white screen. Is it possible to downgrade this phone to an iOS that actually works?