One more small note on the subject of costs:
Notaries usually do not work for free. Therefore, before you request a confirmation or similar from the notary, ask what they want for it. Our notary would have issued the confirmation "free of charge" based on the signed purchase contract. I cannot say to what extent this applies to all notaries (perhaps it is regulated in the schedule of fees).
Why this note? If it is foreseeable somewhere that the tax office will process your application soon, you could calculate very precisely which is cheaper – the 8% p.a. on the paid-out amount or the notary fee.
Regarding the content of the notary confirmation, I agree with . Therefore, I also cannot understand why the notary is being difficult here and waiting for the tax office’s decision. However, back then we paid for our property with equity, so such a problem could not have arisen at all.