Turn on Airplane mode
Restart the phone in Safe Mode
Uninstall recently installed suspicious apps
Remove device administrator access from suspicious apps
Delete suspicious browser extensions or downloaded files
Clear browser data and cache
Run Google Play Protect
Install a trusted mobile security app and scan the device
Update Android and all apps
Change passwords for important accounts
Enable two-factor authentication
Back up important data
Factory reset the phone if malware remains
Restore only trusted apps and data after reset