iPhone 11 (15.1) camera app crashes / all apps unable to be opened

Over the past week my iPhone 11 (running iOS 15.1) has required many hard restarts by pressing volume up/down then hold down on power button. Here are my issues:

1. Failure to open apps (all)
2. Failure to turn off with power button
3. Failure to take photo/video (app crashes instead of taking photo)

Sometimes I can open apps and use normally, but can't take a photo... (app crashes after tapping shutter button).

Is this a known issue with iOS 15.1 or is my iPhone 11 on its last legs?