iPhone and VoiceOver after reset

Hi everyone, after doing a reset of my iPhone, the VoiceOver focus is unstable: when I open an app the focus randomly jumps to an element, and then returns to the top of the screen; also when I flick the focus goes back to the previous element. When I type, instead of confirming the letter I typed, the focus jumps to the text field, so it reads me text field is editing. Before the reset the phone was perfect. I am using iOS 14.7.1. I also tried to do a further reset, this time by connecting the device to iTunes, but the problem did not go away. What can I do? Thanks.