I have the galaxy S9.
I have secure Wi-Fi listed in Wi-Fi settings advanced settings. It is not activated by default. In order to use it you first have to agree to the terms and conditions and then activate it. If you don't want to pay for its premium service you get 250 mb of free bandwidth each month.
I chose not to use it. I don't have any pop-up notifications associated with it.
You might try going into settings /Apps/ select Secure Wi-Fi / tap on the storage entry and clear the cache and data. Tap the back key and find the notifications entry on the list and turn off the notifications.
It's runs at startup but only holds about 12 mb of memory. It's just another app or service option on my phone that I don't use but a lot of people use every day.
try that in safe mode? if u still sees the pop up, then it is what it is. however if u dont see the pop up again in safe mode, then u have to uninstall one by one of the apps to find out which app is causing it
that's where u r mistaken. even for the unlocked phones, samsung has to get approved by the carrier. that's y ppl get the updates all different times.
anyway i would factory reset and see if that helps. if not, then take it to ubreakifix for a diagnosis. worst case scenario, exchange.
Samsung does not get approved by the carrier for it's Factory Unlocked Phones. It's nothing wrong with the phone, it's a software update that Samsung pushed out that is wanting you to pay for secure wifi. See screenshots.