Even if this worked the way you think it did, that helps a speedrun how?

It'll be a while before it matters. I'd say just play what you have until you learn the starts and can pull off decent runs consistently. You'll know when you're ready to get the optimal version

It really depends what you like. I just started running Super Mario World and have been enjoying it, I'm practicing on SNES classic, it isn't the fastest version but is serviceable when you're just starting. There's about a million categories so it is flexible that way, and tons of videos showing the strats.

Also can't go wrong with darks souls, they're pretty popular so it shouldn't be hard to find tutorials.

Overall if you want something with a lot of info out there you want a game that's popular among speedrunners. Go through the games list on this site and sort by most active players. The first few pages will have lots of options.

The correct answer is whatever game I'm currently running Kappa