Hello SamiSaburlu,
To confirm, are referencing the wallpaper going black or are widgets going missing on the Lock Screen? The reason we ask is to ensure there right steps are provided. If the issue is with the wallpaper going black or missing, you'll want to reach out to Apple for additional support. You can find their contact details via the link below.
Contact - Official Apple Support
If you're having issues with the widgets going missing, let's begin with restarting the iPhone using the steps listed below.
- "Press and hold either volume button and the side button until the power-off slider appears.
- Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
- To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo."
Restart your iPhone
Let us know how that goes!