Hello, Sorry, it's a bit hectic here right now. It is an old building that we are currently renovating. The bathroom used to be a bathroom and guest bathroom, that's why there are two windows. I will measure the sill height in a moment... Best regards
I would incorporate the two different windows back into the room layout. Otherwise, it looks like tried but not succeeded. For example, WC under the small window and with a partition wall to the bathtub under the large window. Washbasin to the right of the door against the wall to the children's room. Shower to the left of the bathroom door.
Do the windows actually open in different directions? Quite old? Swap them at the same time.
Consider a decentralized ventilation system for the bathroom.
Just as suggests, I would do it the same way: if the small window is set a bit higher, the separate toilet space would be suitable there. The rest will follow.