Ok, but if it's react it's a web or mobile web project. Then you'll still need to render DOM in the browser and it doesn't matter if you have more or less processing in the backend, you'll always need to care about your frontend.

If you think TypeScript has a lot more benefits then fine, you may go forward with it. I'm just conservative in this perspective. I understand you may transpile (build process), that's fine, I don't like working in Visual Studio, I prefer Atom and having my code without transpiling, not sure how it will work out with your build process when creating a zip to upload to Lambda, but best of luck.