Toilet should then remain unchanged?
Honestly, I always find it quite daring as a layperson to move a toilet from the spot where the wastewater pipe runs. If you ever have a problem, the crap doesn’t just run through the whole bathroom, so you don’t have to break everything up.
As I said: layperson’s opinion.
So sure, shower then maybe 100x140 or something like that and bathtub lengthwise against the wall.
Bathtub with 80 cm width at the top right (for a larger shower there probably wouldn’t be space because of the door), then a shower where the back wall acts as the protection for the toilet. But since the shower should have some depth, you have to look here and figure out where the shower entrance is best placed.
I looked again: if you want the shower to be built-in and without a square shower tray, then it also makes sense to directly build a generous angled area to shower with shelf storage at the top right and the bathtub next to the toilet... or leave the washbasin there and put the bathtub on the straight wall?!
But what do you imagine when you say washbasin at the window? On the 4m wall then, right?
Left side of the plan. So that the daylight from the window can be used at the washbasin.
Just try it out: draw it and move the elements back and forth.
For one person daylight is more important, for another the short way to the toilet, a third again can’t imagine the toilet next to the bathtub.
However, I would make sure that it doesn’t look like everything is just thrown in – there should be a clear line.
I have another idea, I’ll draw it...