Extension and Renovation: Architect Fees Phase 1-4

Thank you very much for the answers!

I am currently out and about with the kids and therefore have only limited access to the plans, which are anyway rather inaccurate. We need to have everything re-measured. Unfortunately, you can't see much in the photos except for vegetation to be removed.

With the new construction prices currently being asked, we can hardly afford demolition and new construction without winning the lottery. Especially since there are still subsidies available for renovation.

The architects who were on site independently (two acquaintances who are retired and the one we might work with) all said that we should not demolish but do a comprehensive renovation. All three also said that an additional floor is cheaper than an extension.
Therefore, I assumed that this is the better option for us.
An extension would theoretically also be possible but would lead to two dark rooms because the house stands on the property line on one side.

That is a really beautiful house!

We once considered a similar project. It was the house of my wife's grandparents. The costs for the extension would have been higher than a new build. Demolition, safety measures, ring beam… complete renovation of the ground floor. We then sold our share to another heir and invested the money into the equity for a suitable house.