Is my phone been hacked?

Hello, yesterday I received a call with a “Potential Fraud” warning. After ringing only once, the call stopped and the phone took a screenshot with the notification “Screenshot not possible.” Since that moment, every time I communicate with Gemini, send voice messages on WhatsApp, or make any phone calls, the microphone icon appears first, followed by a green dot. I haven’t downloaded any new apps or granted any new permissions. When checking apps with microphone and camera permissions, only known and trustworthy apps are listed, and I have performed several scans with no results. Furthermore, the phone can no longer be switched off; when I press the power button, Gemini opens instead. This has been happening since yesterday. What can I do? Regards, Stefan