You have to be careful: the "Easter" package is later than "July" ;-)
: Reasonably, one should not use a fictional sum of money but the available roof area with a suitable orientation as the upper limit for photovoltaics. Because actually, every photovoltaic system is too small. If the money is not enough for the roof areas, leave out the storage initially. You can retrofit it when they become economical. (Currently, they are still about €500 per kW too expensive). And if the money still isn't enough, it almost always makes sense to finance it. After all, it pays for itself.