Is most of non-isolated power supply "safe"?
No, even if that was only a 5V supply for digital logic, it is hazardous and unsafe. So at least your rectangle of unsafe voltages is too small. It will extend to all components and wires going into the box. That is because what you drew as the 0V or ground symbol, will actually have peaks of minus 325V in EU and half of that in the US during the negative sine wave cycle. So your supply voltage is not safe and it must not come contact with humans and it must not have connections to any other devices external to the box.