For a while, there was a library built to do this: https://github.com/guess-js/guess

You can do this with speculation rules too. Your speculation rules are just prescriptive of what you think the user will navigate to next based on your own analytics data (or other heuristics)

Ultimately the pros/cons are similar. You just end up with potentially better (or worse) predictions. I suspect it isn’t much better than simple heuristics such as whether a cursor is hovering over a link or a link is in a viewport. You’d probably have to have a lot of data to keep your guesses accurate

Keep in mind that this will just help with the network load piece, not so much for the rendering piece. Often rendering is actually what is slowing down most heavy frontends. Especially when the largest above-the-fold content you want to display is an image or video