I am already a little (v)ery startled when I read the posts of the OP here.
You really cannot approach a house purchase or
-construction without negative consequences, such as losing track of costs, construction steps, etc..
On the topic of how to manage to maintain a beautiful old gem, I can contribute clear experiences.
We go on vacation much less often. Less because of a lack of money, but because you want to maintain and above all enjoy your house.
My workweek lasts on average 70 hours plus about 10 weekends a year for training that I give or attend. I don’t need a house if I’m away every vacation.
When I have vacation I am in my garden or lying on our Hollywood swing. I don’t need anything else then, but I enjoy the breakfast on the terrace about what we have created for ourselves.
Without these times, I would definitely need house staff, otherwise everything would gradually fall into disrepair.
In summary: Building/buying a house is not the end of it, especially with time-consuming professions.
Sylvia