How to resolve slow iPhone 17 issue after iOS 26.0.1 update?

I have recently purchased a new iPhone 17 and installed iOS 26.0.1. When I try to use it apps like photos and settings freeze and crash constantly. I have spoken to Apple support who suggested turning the phone off and on an again and resetting it. This works for around 10 minutes then it goes super slow again.

I returned the device as the staff thought it may be a defective device after running checks in person. The new device is exactly the same.

I have checked the following:

• Low power mode is switched off
• adaptive power is turned off
• turning down the transparency
• enabling iCloud storage

any advice would be ideal, is anyone else experiencing this? I have had iPhones for years and never had such a poor out the box experience.

[Re-Titled by Moderator]

Original Title: Slow brand new iPhone 17