Hello poluruguayo,
Let's resolve the unexpected shutdown by completing the steps listed here: If your iOS or iPadOS device restarts or displays the Apple logo or a spinning gear unexpectedly - Apple Support that are also listed below.
Check your software
"Make sure that your device has the latest version of iOS or iPadOS and that your apps are up to date. If the issue continues after updating your software and apps, check your hardware."
Check your hardware
"On an iPhone 6 or later, check your battery health under Settings > Battery > Battery Health.
If your battery doesn't need service, and your iPhone, iPad, or iPod touch continues to frequently restart or turn off, contact Apple Support.
If your apps quit unexpectedly, learn what to do.
If your device has a frozen screen, doesn't respond, or becomes stuck when you turn it on, learn what to do for iPhone, iPad, or iPod touch."
Best regards