Controlled residential ventilation: positioning of supply and exhaust air in my designs

You don't have particularly large impacts. It doesn't really matter whether a valve is 1m to the left or 1m to the right. Misplanning can occur with the diameters of the pipes.

Ok, good. Then it really isn't because of me, since I don't determine the diameters. But we had it moved in the living room by about 3m rather than just 1m.

Is the planning done by the architect or does it come from the equipment manufacturer?

The architect only has limited knowledge there. Actually, something like that is done by an MEP planner. Whether they are from the manufacturer, the general contractor, the architect, or somewhere else entirely is not really significant.

Ah ok. Our architect is at least moving the valves for us. But it's good if you can't really do much wrong there...