Start building a house or save more equity?

Ok, you never stop learning. I had definitely read it differently before.

Thank you for the link.

And don’t you find that it contradicts itself or is illogical? How is that supposed to work? Please construct a theoretical case for me with a new building project like the one of the OP. I can’t manage it.

Here is the text again:
You can apply for the Baukindergeld no later than 12/31/2023 if you bought your residential property or received the building permit between 01/01/2018 and 12/31/2020. The decisive date for the purchase is the signing of the notarized purchase contract.
It is important that you submit the application within the first three months after moving in. The move-in date is stated on your registration confirmation.

Where is the problem? Building permit received on 12/01/2020. Then waste time with construction in 2021, then move in/re-register in 2022. Submit application within 3 months in 2022.

n. Sofern Sie Ihren Kaufvertrag zwischen dem 01.01.2018 und 31.12.2020 abgeschlossen haben beziehungsweise im genannten Zeitraum eine Baugenehmigung erhalten haben, können Sie bis spätestens zum 31.12.2023 einen Antrag auf Baukindergeld stellen. Maßgeblich ist, dass die Antragstellung innerhalb von 3 Monaten nach dem Einzug erfolgt.

Ok, got it.

There are exactly 3 important deadlines:

- Purchase/building permit from 01.01.18 to 31.12.20
- Application only up to 3 months after moving in (so don’t miss it)
- Last application receipt by 31.12.23

Of course, there’s also all the other stuff like children and income :-p