Property transfer - how do we do it most skillfully?

No, you simply have to accept the real price as the basis for taxation. The tax office is not cooperative in this regard. How much money actually changes hands is irrelevant and is also not part of the notary contract; it only contains the percentage shares of the property. But the tax office calculates its shares based on the real price. The only option is to make the best possible use of the available tax allowances.

And in this regard, unfortunately, we did not receive any advice whatsoever from the notary. So in the form of: "You can do it this way or that way. The advantage here is xy, the disadvantage xx. The advantage of the second option is ab, the disadvantage cd. Now you have to decide what is more important to you."

The notary is to examine and inform, but not to provide advisory services regarding structuring. If he were also a lawyer, he could (in a lecture, not in the matter in which he is involved as a notary) speak about structuring. Venturing into tax consultancy territory as a notary is too risky for him.

the provisions from land exchange in agriculture unfortunately do not apply to you.....

One of the parties can just found a church; that seems to work as well

Idea: Your brother gives your husband the land share of the building plot amounting to 20k as a gift. You give your brother shares in the parental home plot amounting to 20k. Your husband 'buys' the rest of the building plot from your brother and pays real estate transfer tax on it.

This way, in my opinion, there is no direct exchange. But it only works if you do not have to be registered in the land register for the building plot.

In the end, however, I don't quite understand why the tax advisor doesn’t find the perfect solution. Actually, that's exactly her job. Maybe she has a colleague/acquaintance who knows even more about real estate transactions? It is normal that the notary doesn’t provide much further help.

Maybe you were simply at the wrong notary. A city notary in one of the major Bavarian cities really has no interest in drafting this for you, as in the same time they can earn many times over by simply selling a house. Presumably, your contract was then drawn up by the trainee, who used the best possible standard case. The notaries in the more rural regions of BY usually know such cases better. There are often similar situations regarding farm succession.

, in Bavaria there are no lawyer-notaries. This is a specialty in some federal states, e.g. in NRW.

We were definitely at the wrong notary. We have now implemented the bank's minimum requirements so that we can finally get our financing arranged and will straighten out the rest with another notary. Although we don't live in a big city but in the sticks, and the notary is based in a small town (and since there are no notaries in the countryside, he should actually be familiar with such cases).

I also had the impression that he simply chose the option that involved the least effort for him. That this option means up to €3,000 more in taxes for us doesn't bother him at all.

The contract we ultimately signed was drafted by me over the Christmas holidays - otherwise, we still wouldn't be a step further. Unfortunately, the notary still gets the money.

, in Bavaria there are no lawyer-notaries. That is a specialty in some federal states, e.g. in NRW.

Correct, at this point I just wanted to formulate an answer that is also usable for readers from other federal states – with the core message: even where the notary is also a lawyer, as a notary* he remains purely an informing certifier and does not become a partisan advisory party as one would otherwise expect from a lawyer. As a lawyer, he could justify advising in a tax-structuring manner with his loyalty to the party – as a notary, on the other hand, he would trespass without excuse on terrain reserved for tax advisors. That could endanger his admission, so his restraint must be understood in this respect.

*) the "combined" lawyers / notaries must separate both roles and therefore initially record that they have not been involved with the same matter in the other capacity. Some federal states therefore prefer to separate the functions right away – but as far as I know, the notaries then always have districts like chimney sweepers ;-)