const text = `KI Quiz Teil 2 - jetzt wird's schwerer "
"
"Letzte Woche haben wir die 5 Einstiegsfragen gesehen:
"Viel Vergnügen!`;
// Strip trailing quotes
let cleaned = text.replace(/ "\n/g, '\n');
// Strip quotes on their own line
cleaned = cleaned.replace(/\n"\n/g, '\n');
// Strip leading quotes
cleaned = cleaned.replace(/\n"/g, '\n');
console.log(cleaned);