Thanks for sharing your positive comments with screen shot of your Samsung Galaxy A12 here, updated with the latest software, the Android 13, One UI 5.0.
Thanks for your inquiry, here.
Here’s how you can disable the auto-change of wallpaper on your Samsung Galaxy phone running One UI 5.0.
Step 1. Open Settings on your Samsung phone and go to Wallpaper and style.
Step 2. Click on Browse my wallpapers and then tap on the Wallpaper services tab.
Step 3. Select None from the available options and then click the Apply button.
Be sure to click " ✓ Accept as Solution" when you find an answer that works for you.
Thanks for the feedback.
Please check whether you have an app i.e. Bing daily or your Gallery selected as daily slideshow for your wallpaper.
Then, restart your device.
For more assistance, you may contact us on our online Samsung support channels below.
If the problem persists, immediately bring your device to the nearest Samsung Authorized Service Center.