You may also try to enter Safe Mode (or if possible, do a factory reset). If the issue still persists despite doing either (or both), it's possible that the issue is at hardware level.
We are sorry about your experience with your beloved Samsung Galaxy A71 having ghost touch issues, and we apologize for the inconvenience it caused you.
If it happens on my device, I will get worried too. But don't worry, we are here to guide you, and offer solutions to restore your device to optimum performance.
If that doesn't work, you may submit an error report through Samsung Members app as follows:
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 "Sensor/Touch".
Step 4. Describe the problem in details and SEND.
If the problem persists, immediately bring your device to the nearest Samsung Authorized Service Center. Rest assured that our Samsung engineers and technicians are competent to assess your device, offer suggestions, and provide prompt solutions to restore it to optimum performance.
For more assistance and guidance, you may contact us via our online Samsung Customer Care support channels below.