Hi sleighcake,
We appreciate you reaching out to us.
We’d like to gather additional details that may help us be in a better position to assist you.
- Are you experiencing the issue with every wallpaper that you try?
- Are you using a wallpaper from the Weather & Astronomy section?
- Are you using a third-party wallpaper?
We'd also like to set your expectations. Some wallpapers are dynamic. For example, the image may change if it's cloudy or as day turns to night.
Also, since you are using a version of the iOS that is still in a beta phase, issues like this may arise.
If you’re having any issues using the public beta, we welcome your feedback here: Apple Beta
You also have the option to use the built-in feedback app. As mentioned in our Apple Beta FAQ page, "The iOS, iPadOS and macOS betas come with the built-in Feedback Assistant app, which can be opened from the Home screen on your iPhone or iPad or from the Dock on your Mac. The Feedback Assistant app is also available from the help menu of any app by selecting Send Feedback. If you’re running the tvOS, HomePod software or watchOS beta, you can submit feedback through the Feedback Assistant app on an enrolled iPhone, iPad or Mac. When you experience an issue or something does not work as expected, send your feedback directly to Apple with Feedback Assistant."
Apple Beta — FAQ
Take care!