iPhone 15 won't play videos

misinformed_millennial wrote:

Since doing that

It's not always the iOS update's fault!  Many things can cause phone problems.  If you tell people you think it's an iOS update, it might make it harder to fix or find a solution for the real issue.

Remember, the right question often leads to the solution!

Was/Is your device Jailbroken? If that's the situation, please be informed that attributing the issues to iOS updates may not be accurate.

iOS updates aim to enhance user experience, boost security, and fix bugs rather than disrupt core features. The majority of the issues after updates might stem from underlying, unmentioned factors. Updates won't typically alter personal data but may refine settings or features. Backup before major updates for safety. Review Apple's update details and backup advice for a smooth process.

Kindly consider checking your settings and addressing any device issues before attributing the issue to external factors. This could be a pure coincidence that the iOS update affected the iPhone functions.

Before initiating a standard iOS update, it's advisable to create a backup. Have you completed this step? If yes, proceed with the restoration from the backup.

See what each update does: OS — iOS 26, About iOS 18 Updates, About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...

Your iPhone may not have enough space to store all high-resolution photos and videos from iCloud.

Please compare 

Settings>your name>iCloud>Manage Storage

And

Settings>General>iPhone Storage

This will give you a fair idea of how to manage your device storage.

Some of the links below may help

1. Manage iCloud Photos iCloud Photo Library Help - Apple Support 
2. Manage your iPhone Storage --> Manage your photo and video storage - Apple Support
3. Manage your iCloud Storage → Manage your iCloud storage - Apple Support