With over 7 years of in-depth knowledge in web development and a full command of React and SPFx, I am well positioned to troubleshoot the CORS error that you are currently encountering in your project. Not only am I familiar with API integrations, but my extensive experience allows me to efficiently diagnose and resolve issues like these in order to optimize your webpart's fetching capabilities.
Moreover, my vast skills spanning from front-end technologies -- such as JavaScript, React.js, Angular.js -- to back-end proficiencies including Node.js, Django and database management systems like SQL Server, SQLite -- will surely come into play in RESTful data presentation on the user interface.
Lastly, I believe a successful professional collaboration is not solely about skills and experience but also about meeting clients' expectations effectively. Thus, not only will I resolve your CORS issue swiftly, but I will also communicate transparently throughout our journey to ensure that every aspect of your needs are understood and met. It would be an honor, Muhammad to contribute my technical expertise into making your project a success; let's solve this CORS error together!