Android Security Breach Recovery

My Android smartphone has been hacked, and I'm being constantly monitored. I need an expert to help secure my device and remove any threats.

Issues I'm facing:
- Unknown apps being installed
- Strange behavior or performance issues
- Unauthorized access or data leaks

I have already attempted a factory reset without success.

Ideal Skills and Experience:
- Strong background in Android security
- Experience in malware removal and threat mitigation
- Knowledge of monitoring apps and unauthorized access prevention
- Ability to secure data and restore device functionality

Please provide a detailed plan of action and any relevant experience.