If your children are healthy and not disabled, then they can safely go up or down any staircase. At first, it is always a bit difficult, but countless generations of humanity have managed to safely navigate any kind of staircase. I think you are exaggerating. For safety, it is crucial whether the staircase is open or closed and whether the children can fall through the railing on the side. Whether the staircase is a normal turn or has a landing is really not that important. Meaningly, one can even say that a quarter-turn staircase stops a fall and is somewhat shorter and thus safer on a straight stretch. Then you would have to take a twice quarter-turn staircase with narrow balusters, enclosed construction, and a safety mat at the bottom.