To immediately announce error for control/input I have 2 choices:

1. append HTMLElement to document with role 'alert' and error-message. NVDA reads alert. [errorMessageHere]

const el = document.createElement('div');
el.setAttribute('role', 'alert');
el.className = 'visually-hidden';
el.textContent = 'Some message here';
document.body.append(el);

.visually-hidden {
  position: absolute;
  height: 1px;
  width: 1px;
  top: 0;
  left: 0;
  overflow: hidden;
  clip: rect(1px, 1px, 1px, 1px);
}

2. Use window.speechSynthesis.speak. NVDA announce [errorMessageHere]

const speakObj = new SpeechSynthesisUtterance('Some message here');
window.speechSynthesis.speak(speakObj)

What I really notice that in NVDA you can disable text-to-speech and show speech-viewer. First case will be logged into speech-viewer but 2nd case - not. NVDA directly announce text when NVDA is opened even if text-to-speech is disabled.

I'd prefer to use window.speechSynthesis.speak instead of creating extra HTMLElements per each case when some details/errors must be announced but I'm not sure is it correct alternative of role 'alert' since window.speechSynthesis.speak is not logged by NVDA at all (but only announced).

Could help me to understand what the best way to be announced/read by screen reader ?