Apps in China displaying ads and opening third-party apps after background mode

If you're using a 3rd party app, especially one you aren't paying to use, you're going to get advertisements and that's not within Apple's control in any way. App developers aren't charities. They need to make money to deliver their app. If they offer the option to pay for the app, they usually in return give you an ad free experience. But if you don't pay for the app, they're going to show ads to you as they are paid by the companies who advertise on their app as a means of making a living.

Your options are:

1. If the app offers an ad free paid version, pay for it.
2. Don't use the app, if the adds are too intrusive.
3. Live with the ads, if you don't want to pay for an ad free version.
4. Understand that Apple has no control over what 3rd party app developers do in their apps.

Pay app vendors to remove advertisements, or acquire apps from paid sources that aren’t ad-supported.

Apple Arcade games don’t typically have advertisements, for instance.

Advertisements are present across all platforms that offer cheap or free apps, and are quite often how the app developers support .

If an Android or other phone better for your preferences, by all means use it.

“If an Android or other phone better for your preferences”

If he thinks ads are bad on an iPhone, Android ain’t the answer.

Same apps that are free are still going to show ads.

Also since google doesn’t run an AppStore in china, lots of side loading and dodgy appstores providing virus/malware filled applications.