Sorry, but until Firefox runs JavaScript code at least on par with Safari, it isn't a good option for some of us. I am the author of a reasonably large web app ( https://partsbox.io/ ), and in real-life performance on a Mac, Chrome is #1, Safari follows right behind it, and Firefox lags far behind. So, Firefox isn't "faster" and doesn't "lag less", quite the opposite.
In any case, I'd like to try to figure out what's going on here. Is the problem reproducible with the publicly available demo of partsbox? If so, what are the steps to reproduce? That is, what operations are you measuring?