Somewhere there is a limit, and if you are a cent below it, the light just turns red. Have you already discussed with them what kind of commitment would be needed?
Everything goes through financial advisors and the most important paragraph of the long email was:
We are unable to comprehend your total cost breakdown. Market-related increases in the value of the property in the meantime are not to be recorded as "property costs." The actual purchase price is decisive here. The total costs should only reflect the amount that generates an actual payment / cash flow. The exception would only be family purchases (usually here the purchase price is below the market value).
I would also recommend the Volksbank in Ortenau to you. At least they went through a similar structure with me (mortgaged condominium to represent equity). But I think they no longer offer interest rate fixations longer than 15 years.
Does not want longer than 15 years either. I already inquired at Berliner Volksbank, but they do not grant real estate loans themselves, they act as intermediaries.
Feel free to ask at Volksbank Ortenau, thanks for the tip.