So, I don’t see a T-shaped bathroom from the dimensions here. The page suggested above offers a good idea, but there the bathroom seems to be nearly 3 meters wide. The space behind the door of about 60/70 cm should be well used for a double washbasin on a countertop. A slightly asymmetrical layout towards the exterior wall would be ideal. Behind the wall, the space can still be used for a wall cabinet or shelf brackets. I would probably consider a walk-in shower feasible, but with other compromises.
