How do you let your character move but not attack during the intro sequence, and ensure hitting an attack button won't skip this intro sequence, and ensure the player won't be teleported back to the starting position when "Fight!" is announced?

I searched for this but all I could find was decade-old links and dead sites.

Melty Blood has the right idea (skip to 4:56) https://www.youtube.com/watch?v=jtsswyTxH2o

But every Melty Blood character I download can't move at all during the intro, let alone jump or air dash. Some characters prompt the player to pick a mode like Melty Blood/Original/ReAct or a Groove but that's not what I'm after.