JSFiddle - React, Tailwind, and code Playground

JavaScript

function unicodeToChar(text) {
   return text.replace(/\\u[\dA-F]{4}/gi, 
          function (match) {
               return String.fromCharCode(parseInt(match.replace(/\\u/g, ''), 16));
          });
}

const unicodeStrInput="\u0423\u0432\u0430\u0436\u0430\u0435\u043c\u044b\u0439 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044c!\u041e"
console.log(unicodeToChar(unicodeStrInput))