Open Settings
Tap Apps or Apps & notifications
Find the app causing the ads
Tap Uninstall
If it cannot be uninstalled, tap Disable
Go to Settings
Tap Google
Tap Ads
Turn on Opt out of Ads Personalization
Go to Chrome
Tap the three dots
Tap Settings
Tap Site settings
Tap Pop-ups and redirects
Turn it off
Tap Ads
Turn it off
Clear browser data
Go to Settings
Tap Apps
Tap the suspicious app
Tap Permissions
Remove unnecessary permissions
Go to Settings
Tap Security or Privacy
Run Play Protect
Install apps only from the Play Store
Avoid unknown APK files
Restart the phone after changes