Property (Loan / Sale)

Hello dear forum members,
I have the following concern.

I own a plot of land (value approx. €300,000) free of encumbrances. It is currently listed for sale through a bank.

Unfortunately, there is no buyer in sight yet, but I currently need about €25,000 capital for an investment.

How can I best and, of course, most cheaply obtain the capital with this basis, which I only need until the sale of the land.

My situation:
I am 44 years old and self-employed since 1998
I built a house in 2012 on which there is still an outstanding debt of €140,000. (monthly rate of €820, fixed interest until 2033)

I look forward to exchanging ideas with you
Nordmann

Do you not have a line of credit with your bank? I (not self-employed, purely a private individual) can draw up to €25,000 directly and also repay it immediately. Well, it costs ~8.5-9% interest, but if it is only for a limited period, that might be something, as it is very flexible?

Consumer credit. I constantly receive such offers, and yes, also from my [Hausbank].

Apply for a line of credit through Smava or similar. You can't do anything with the property at first (at most with the house bank, which is supposed to sell it, within the framework of a positive-negative declaration).