We're sorry to hear that the recent update of your Samsung Galaxy A13 caused an issue with missing Edge Panel feature for One UI 5.1.
I really understand what you are going through, expecting your device to be better after an update but finding out differently. If it happens to me, I will feel bothered too.
Before you try out the recommendations below, be sure to check if your device's software and related apps are updated to the latest version. To update your mobile device's software, follow these steps:
Step 1. Long press Samsung Members icon on Apps screen and tap Error reports.
Step 2. Tap OK on agreement popup to send system log data.
Step 3. Select Symptom category "Settings/System".
Step 4. Describe the problem in details and SEND.
For more assistance and guidance, you may contact us on our online Samsung Customer Care support channels below.
I had the same problem and contacted Samsung support. It was a power setting that caused the issue. Pull down the quick settings, tap battery saver, open details, and be sure limit apps and Home Screen is toggled off.
setting that was hiding the Edge panels. Go to Battery Saver details and make sure limit apps and home screen is toggled off.