Did the notary charge us too much? Are the land registry costs too expensive?

And then €750 to type 2 minutes of data into the PC.... That only happens in Germany

Funny argument.

There are now nationwide online cadastral maps in Germany available for free use, along with further data, some of which are chargeable or can be provided for very low costs for BV or even free of charge.

All of this can be generated at the push of a button within minutes and meets high standards regarding reliability, completeness, and accuracy.

Is it too much to understand at this point that something like this takes decades (!) to build up and that updating/maintenance requires manpower as well as financial resources every year?

It does not fall from the sky.

To the point: the notary's costs are legally regulated, as already described, obviously correctly arranged and oriented at the lower level. However, this can also be checked by the responsible chamber, the check is usually free of charge – I would only expect that the chamber will revoke the fee notice... and increase the costs.