Why are the apps on my iPhone crashing
Why are the apps on my iphone 15 Pro Max crashing? was happening before and after the recent 18.3.1.
Question marked as
If you have any add-on VPN apps, remove all, restart, and test again.
Perform a forced restart: Force restart iPhone - Apple Support
Failing that, back up, reset, and restore: Restore your iPhone, iPad, or iPod to factory settings using a computer - Apple Support (includes links to backup, restore)
If that fails, contact Apple Support.