Never had a pop up ad on my Android, ever, ever, ever. It's probably not Uber, just cuz it's an Uber ad. Maybe you installed an app that you permitted to do this (just cuz apps are free, doesn't mean you should download them. They aren't giving those things away, they're selling access to your device, which you give them by downloading and approving all the permissions they asked for). Having Uber on your phone may tell the ad ware what sort of ads to send, so you get an Uber ad pop up.
One time I read a news story on my laptop about someone who murdered, chopped up, and stored a body in their suitcase. On the right was an ad for luggage. Were it cutlery, that would have been even better, but the computers are just developing their sense of humor. They'll improve.
Is there Purify or 1blocker for Android? I used to use 1blocker then switched to Purify on iPhone. I think AdBlocker has an 'acceptable' ads system (i.e. companies who pay to bypass the blocker, and agree not be 'too intrusive').