The problem was somewhat simple and wierd, my react file had an import statements looking like these :-

import * as react from "react";

while the esbuild compiled the jsx to React.createElement(...), noticing that my imports declared 'react' with smallcase 'r' while the jsx was transpiled with React.createElement with uppercase 'R'.
Fixing my imports to have a uppercase 'R' fixed the issue. Looks like esbuild doesn't look at the react imports while transpiling jsx.