React development builds are so laggy that even the most basic of optimization I make to speed it up ends up as a significant improvement in performance in the production build

Seems you may have overlooked some of the best practices...
Did you write some shouldComponentUpdate for example?

@react-guy I'm only using hooks and functional components, and yes, all the proper code is covered in multiple implementations of useEffect. I'm rendering thousands of elements on the HTML5 canvas with frequent updates to many of them, which lags out in dev but runs so smoothly in prod .