I think the speed run should be started when the first text pops up or when you gain control of your character, because of differing load times. I know it isn’t a long time in between hitting the difficulty then being able to start playing, but every time I do a practice run it takes about ten seconds to load the world before I actually get to the text. (I play on switch and Xbox, which have long load times compared to the ones on PC from all the speed runs I watched.) I guess it’s a quality of life thing, and I’m kind of a stranger because I haven’t posted a run yet (I’ve been practicing and once I figure out how to record I will post one), but I really think this would improve runs for console players.
I know i'm a year late, but this would also be nice for coop runs. It takes longer because you have to speedrun pressing the a button on control and space multiple times, it just wastes seconds. It should be at the moment you see your character stand up.