I know how, if you want to remove these ads, just follow these steps :
So I went to my phone (which is old and still has service to call people lol) that had ads and I kind of removed two days ago but before those two days the phone still had ads popping up. So, I went into the phone setting and I uninstalled this app called, "still" and after that, I saw google play protect found 4 apps that was harmful and I went there to uninstall it (which was the apps that pops up ads) and later, there was no more ads. But, I also realized that the app, "still" was doing something so, Google Play Protect didn't know that the 4 apps that kept popping up ads.
What was the phone from?
Yeah, about that it was the UL40
Also, it was made by ANS (or America Network Solutions) the phone that always pops up ads
If the problem keeps persisting I don't know what I can help or maybe I can help.
Welp, have a good day!