I can't get how to add line breakers to a copy buffer that then can be pasted in google sheets with breaking lines. I need a HTML (br / p) behavior. When we select text with such line-breakers and past it line-by-line in sheets.

I don't want to create a new window for that:

 let string="";
 document.querySelectorAll('p').forEach(el => {string+= el.innerText + "<br/>"});
 let newWin =  window.open("", "Title");
    newWin.document.body.innerHTML=string;
    newWin.getSelection().selectAllChildren(newWin.document.body);
    newWin.execCommand("copy");
 }