Do you think if a time player and a space player combine their power on one of the portals of Skaia that would allow them to travel anywhere anytime ?

Hard to say since we don’t exactly know the mechanisms through which the defense portals actually work? Likely not however- After all the energy of the Scratch is required for something as minor as flipping a few of the portals’ destination- Then again it’s a full Timeline reset so maybe there’s more to it.