There isn't a built-in way to allow certain images to be used as wallpapers. With iOS and iPadOS you can restrict, or allow changing wallpaper. That is as deep as it gets.
If you want to apply wallpaper to an iOS or iPadOS device you can do so using the Automated Management tab of a Smart Device Group and choose to set it as a Lock, Home or both.
If you really wanted to get fancy you could build an app in Teams, Slack or whatever your company uses to allow users to select wallpaper and move them into that Smart Device Group using the Jamf API while also restricting changing wallpaper. This would effectively do what you ask even if it isn't straightforward.
Alternatively you could push out the Jamf Setup app and sort of do the same thing where they can choose the wallpaper they would like by changing the Jamf Setup Role and only changing wallpaper instead of the entire configuration. The only downside here is that there is no way to preview the wallpaper inside the Jamf Setup app whereas with a custom app in Teams or Slack or whatever would allow you to do something like that.
