Thank you for the answers. The idea was to make the building savings contract ready for allocation as quickly as possible with high one-time payments. Then to use the secured interest rates to start looking for an apartment. I was also told that banks accept the building savings contract that is not yet ready for allocation as existing capital and consider it in the loan calculation. Does that make sense?
So with a one-time payment (25-30%), depending on the variant, the building savings contract should be ready for allocation in 2-3 years (if you still save a little monthly).
And it does make sense, firstly: if the interest rates are then at 3-4%, and you have part of the loan through the building society at 2-2.5%.
Also, the bank then finances the first mortgage rank = if, thanks to the building society, you have an additional 30-50 thousand euros of equity for the first bank, you get better interest rates!
So with the current interest rate situation, it certainly makes a lot of sense. If interest rates fall back to 1-2%, then it only meant costs for the case, but it’s like with insurance: it’s nice if you don’t need it, happy if you have it!