Problem solved…
I created an AR application (ARCore) that displays a 3D model after detecting a QR code. After starting the application on the Poco X3 phone, the object appears and immediately disappears, or moves around the edges of the screen. I tried on Unity 2022 and 6. I tried different versions and configurations and still the same.
Video shows app in action: https://youtu.be/ZdyFGIVY7pk?si=SsjsRrNWs91OmpvX