EDIT: Found some more relevant
Sage Advice to consider.
Question: "So how does that work? Each dash is a move action or is it just you may move again?"
Answer: "On your turn, you can move. Dash increases how far you can move on a particular turn."
Place that in context with...
Question: "If you ready the Dash Action, can you then move up to twice you speed in reaction to the trigger?"
Answer: "Dash gives you extra movement. Off your turn, you have no movement. E.g., 0 ft. + 30 ft. = 30 ft., not 60 ft."
That leads me to the conclusion that if you take the Ready action to Dash, nothing happens when you take your reaction because your reaction takes place on another combatant's turn.