So I have an Idea to save some fractures of a second in all network speedruns and that the world record didn't use in his run. So basically when you select the first level you can choose whatever level you like (under my understanding). So when you choose the level that requires the most navigation (hopping run) you will cut of time that you would waste navigating through the menu.

This is a good time save agreed. The only reason it’s not currently used in many of the top runs is because it tends to be easier overall to consistently complete runs if you start at the ones that have the highest chance of killing the run, since it leads to many more runs being completed in the same time period (thus increasing chances of PBing). Plus considering how much of an opportunity there is across each of the levels compared to top runs currently to regain the time lost by not doing this trick it loses a bit of the viability.

Obviously however a time save is a time save so maybe one day when the record gets more optimized this could be a big help in driving it even lower.