The Ready action is described as follows:
First, you decide what perceivable circumstance will trigger your reaction. Then, you choose the action you will take in response to that trigger, or you choose to move up to your speed in response to it.
So, is there anything preventing you from moving your full speed and then taking the Ready action for another (off-turn) full-speed movement? The above quote seems to allow it, but it just feels slightly weird to me, so maybe there's something else prohibiting it.
Increasing your speed is of course no reasonable motivation for such a strategy, since you might as well just take the Dash action. This strategy however would effectively let you split up your Dash speed over your and someone else's turn, which might come in handy here and there - even though it costs your reaction.