Wastewater plan for new construction on the upper floor (bathroom)

Dear forum,

I would like to know if our wastewater plan is good. We have concerns that it could lead to problems because the wastewater pipe of the WC is too far from the downpipe.
Also, we find it strange that the shower is connected to the same pipe as the shower.

Could it happen here that feces come from the shower or that there could be odor nuisance?

Moreover, we find it strange that the shower was connected to the same pipe as the shower.

I also find that strange.

The shower and toilet have a trap. Under normal weather conditions, the ventilation should work.

The pipe from the toilet is lower than that of the shower. Normally, no feces should reach the shower unless the drainpipe is blocked.