Help, found a building plot, now what next?

Hello everyone,
after we had already been dealing with the topic of building a house for a while, we randomly found a building plot that appeals to us. However, since we were not yet at the point of selecting a construction company and we have never bought a plot before, some questions are now arising.
We do not want to "miss out" on the plot but also do not want to approach it "too naively." We want to build without a basement.

The plot is currently undeveloped and is located in a village in Brandenburg, no development plan but §34. There is an old preliminary building inquiry. There is no specified floor area ratio or site coverage ratio. It is a building gap; the neighbors are a mixed rural, agricultural community. However, the plot is located in the area of an archaeological monument (Stone Age settlement) - like many villages here, unfortunately. Utilities are probably located in the street in front of the plot. The plot is level and almost ungrown. As always, there are several applicants.

Questions now:
1. What documents and information can we expect from the real estate agent or need in order to clarify with the authorities before buying the plot whether we can build there what we want?
(Can we also expect documents showing the exact dimensions of the plot and the location of utility connections?)

2. Since there are other applicants besides us, what can/should be done to initiate clarifications without incurring high costs in case we do not get the plot?

2. We know roughly what the house should look like and have had contact with some construction companies but have not yet become concrete. Is it necessary to choose a construction company (prefabricated house) BEFORE the purchase, or can that wait?
For us, this felt like the chicken and egg question. Which comes first? If I have the plot first, I do not know if my desired house fits on it. If I want the house first, I can hardly plan it without knowing the plot. What is the best approach here?

3. Which authorities should we contact before buying the plot (preferably free of charge and without long waiting times) to find out whether we may build what we want there and possibly what development costs/other costs to expect? (Building authority, utilities, monument protection) Should we do this ourselves or better let the construction company handle it?

4. The issue of the archaeological monument worries us because of uncertain costs or construction delays. Does anyone have experience or tips here? We will probably have to reckon with this elsewhere in the area, so should we perhaps approach it? Is it common that the buyer has to bear these previously unknown costs? Is it possible to determine these costs in advance?

5. Which development costs are usually borne by the buyer, or (have already been borne), which could still be incurred (utilities in the street)?

6. Does the plot need to be surveyed again by us, or is it common that it already has been or was surveyed at the last sale (a few years ago)?

7. What about soil investigation? Should this be done before the purchase?

8. How is it with the price? We know the standard land values. But what if the plot can only be purchased with a higher bid? Will the bank finance that even if the purchase price is above the value?

What else should we think about?

Thanks in advance for every hint and advice!

1) A cadastral excerpt should be obtainable from the surveying office or similar, possibly from the seller or realtor. 2) You do not need a construction company to purchase the property. However, advice and support might be useful to clarify what is allowed to be built. For this, a "construction company" is rather unsuitable. Possibly an architect. 3) Call the building authority and ask. It might work, or it might not. Only a building inquiry is binding. 5) Inquire with the utility providers: Telekom usually has a flat fee of €600, electricity with the local grid operator, water with the local grid operator, sewage usually with the municipality. 7) It is usually recommended. But you can also, for example, go around to the neighbors and ask – then you usually already know whether extremely expensive foundations like pile foundations or soil replacement are required. 8) Ask the bank. We bought at about 50% above the standard land value. It was not a problem; the banks are familiar with that. Ask about contaminated sites, previous development and use. Look at the street, and if necessary, ask the municipality whether there are any outstanding costs for road renewal, or if such is planned soon.