Controlled residential ventilation manufacturer selection - How to approach?

True, photovoltaic can be installed later, controlled residential ventilation rather not or significantly more expensive

Photovoltaics can be done later, controlled residential ventilation rather not or much more expensive

However, photovoltaics have a much higher benefit (not to mention the environmental one) than controlled residential ventilation.

But we are going in circles. There are fans of controlled residential ventilation and those who don't necessarily need controlled residential ventilation. We can agree on that.

I just wanted to express that if you actually want both but only have money for one, you should rather choose the controlled residential ventilation first, since the photovoltaics can always be done later.

Of course, I am pleased about the lively participation here. Many thanks already.
Now to the comments:
1) In the "Technical minimum requirements" for KfW55, a controlled residential ventilation system is mandatory if you choose a GAS condensing boiler. I am not yet convinced by heat pumps and I am "sensitive to noise". Even though modern heat pumps are very quiet. They are not silent. If we already make an OT digression about heating: I could only imagine a heat pump with an ice storage tank. Unfortunately very expensive. And in terms of heating, you can still switch after years.
2) My installer definitely wants to push a Viessmann controlled residential ventilation system on me. But I am not convinced by Viessmann. Apart from Viessmann, they also do Pluggit and Helios. But I do not want to base this decision on my installer’s "affiliate" contract. I want to choose the controlled residential ventilation manufacturer according to my requirements and then, if necessary, look for a suitable installer.
3) The tip "Erlus" was great. I did not know it yet. I find the idea of the "chimney" as a supply and exhaust air "riser" very good. I will take a closer look at that.

Does anyone have any other tips?

One more tip: the Zehnder Q350 is a very good model. Take a look at it. I actually only know satisfied customers, I installed it myself.

I have put my first thoughts on paper.
orange: exhaust air valves + pipes
blue: supply air valves + pipes
red: exhaust air to outside
green: supply air from outside

What do the experienced builders say about the placement of the valves?