why is it that #text HTMLElement reference to parent Node sometimes return null

I am getting focused element target with selection API this way below

const target = window.getSelection()?.focusNode;

And when the focusNode is #text HTMLElement, I would want to get the #text Node parent node by doing the following below

console.log((target as HTMLElement));console.log((target as HTMLElement).parentNode as HTMLElement);((target as HTMLElement).parentNode as HTMLElement)?.append(  rows);((target as HTMLElement).parentNode as HTMLElement)?.append('<click here to continue new line>');(((target as HTMLElement).parentNode as HTMLElement)?.childNodes[  ((target as HTMLElement).parentNode as HTMLElement)?.childNodes.length - 1] as HTMLElement).innerHTML = '<click here to continue new line>';

This works all the time on chrome, but work on mozilla and fails sometimes along the line where I want to get the parent Node.

((target as HTMLElement).parentNode as HTMLElement) returns null 

I have tried to run them in a setInterval function below but it still not working.

let counter = 0;const tt = setInterval(() => {  const     t1 = (target as HTMLElement),    t2 = ((target as HTMLElement).parentNode as HTMLElement)  ;  if(t1 !== null && t2 !== null) {    ((target as HTMLElement).parentNode as HTMLElement)?.append(      rows    );    ((target as HTMLElement).parentNode as HTMLElement)?.append('<click here to continue new line>'    );    (((target as HTMLElement).parentNode as HTMLElement)?.childNodes[      ((target as HTMLElement).parentNode as HTMLElement)?.childNodes.length - 1    ] as HTMLElement).innerHTML = '<click here to continue new line>';    clearInterval(tt);  }  else {    if(counter > 30) {      clearInterval(tt);    }  }  counter++;}, 1);

Please I need help on how to solve this problem in such a way that as long as the #text HTMLElement is not null or undefined then its parent node should never ever be null or undefined.