You may have adware / malware on your device causing this behavior.
You could download the "Nicecatch app" and enable toast history in the app settings. By doing this, it will hopefully let you know if adware /malware is sending those pop-ups, and then you can proceed to uninstall the suspicious apps immediately.
Sorry to hear about the pop ups I know that is frustrating after awhile but I was able to find one article that could be of help if you haven't preformed any troubleshooting yet on your device, hopefully this helps provide an easy fix. link down below
☆ Check for routines If apps/dialogs are opening unexpectedly or under strange conditions (such as when charging, certain times of day, or arriving at certain locations,) make sure you have not inadvertently set up a routine. Some users have reported that routines (Samsung’s automation feature) were accidentally enabled without their knowledge. Open Modes and Routines and check if something unusual is set up.
☆Scan your device for malicious apps. Go to Settings >Device Care > App Protection > Scan phone to identify any potential threats or malicious apps on your device.
☆ Use Samsung’s Nice Catch app Some apps are malicious and can have undesirable effects on your device when installed, knowingly or unknowingly. If you’re experiencing unexpected or unexplained ads, pop-ups, wake-ups, etc., Samsung’s Nice Catch app can help identify the offending app so that you can delete it.
Turn on the various categories in Nice Catch. When the undesirable behavior happens again, check Nice Catch to see which app triggered it.
