Turn on Airplane mode
Disconnect from Wi-Fi and mobile data
Restart the phone in Safe mode
Uninstall suspicious or recently installed apps
Remove admin access from unknown apps
Clear browser data and downloads
Run Google Play Protect scan
Update Android and all apps
Clear cache for affected apps
Reset app preferences
Change passwords for important accounts from a safe device
Enable two-factor authentication
Back up important data
Factory reset the phone if the problem remains
Restore only trusted apps and data after reset