Also happening to me on 13 Pro. This is definitely a software issue from iOS 26.3.1 since all of these have have work-arounds that will allow use of the selfie and wide angle cameras.
NOTE 1: I have not found a way to make the wide angle lens work without a re-install of iOS... but even then it only works for about an hour, and then gets stuck again.
NOTE 2: 3rd party camera apps seem to have less of an issue switching between cameras, though all still struggle with the wide angle camera.
Test 1:
- Open Camera app using app icon OR tap in control center
- Switch to selfie cam or wide cam
Result: app display does not work, app becomes unresponsive in some cases.
Test 2 (workaround for selfie/front):
- Open control center (swipe down from top right of screen)
- press and hold camera icon
- when sub-menu pops up, slide finger to selfie
Result: selfie camera works as intended, rear 1x will not work