A purchase from the municipality also usually does not occur at market value, otherwise 20 (200) bidders would not be fighting over the building land and the municipality would have to decide by social points or lottery.
Nevertheless, two financing brokers and the state bank clearly refused, no chance to use the current value as equity, at the earliest after 5 years.
Somehow logical, they do not want to artificially reduce the loan-to-value ratio through miraculous money creation.
Actually illogical, because if one had not bought building land with the equity, but perhaps shares, which one sells the next day for double, then the banks obviously have no problem with that. Or even sells the property at market value and buys the neighboring plot with the proceeds...