I've just seen an Article talking about adware, if it's the same one they say I need to replace my device entirely. I've already hard reset my phone once this has happened before, and chances are I could've got it through large apps like Facebook or Twitter, apparently hackers repackage said apps with ad ware but leave the app function making it very hard to remove, pretty much impossible because it's been "trojanized". Its even been found in WhatsApp which is BUILT IN TO SAMSUNG PHONES. Honestly I'm tired of all the shit this s8 has put me through, first chance I get in switching to iphone.
Sorry you feel that way, yeah it's hard to find the balance, Android allow for freedom of creativity so you can basically do what you want with the device but it puts security at risk where Apple is closed off but very secure. But as for your matter at hand I guess hard reset might be your best bet. If you haven't tried this step then maybe attempt this first, clear the device of Dianxin as best as possible and then turn your phone off and then run it in recovery mode and try wiping the cache partition. it's helped with various other things and worth a shot over hard resetting.
When running this app go to show concerns than go to ad networks( this option is shown in tab) select the network that you previously said is a culprit. Selecting this network will show which app is a causing all this ads. I hope this help.