Financing land and house construction

As far as I understand, you don't have a general contractor/general building contract or offers for a house yet, so you don't actually know how expensive the house will be?

So it doesn't make sense for you to already take out a higher loan now, because you
1. only pay no commitment interest for a certain period (usually 12 months)
2. might need an expensive additional financing because the construction turns out to be more expensive than you currently think
3. don't have a cost breakdown that banks normally want to see.

Or do you think the bank will simply register a higher land charge even though you are initially financing a much smaller amount?
Whether that works and is possible, I don't know. Despite everything, the likelihood is still high that the land charge will have to be changed because you need to finance a higher amount than planned.

Yes, the land charge can already be registered at the "correct" amount now, but you don’t even know your house yet, so how do you know the correct amount of the land charge?

Moreover, in most cases it is more expensive to have a higher land charge assigned than a smaller land charge, since often the "countervalue" of the land charge serves as the valuation basis.

No, I don't know the exact house construction costs. I would have assumed the maximum available budget, meaning the max loan we can afford. Ok, according to such an online mortgage calculator, an assignment probably costs around 300€. I think it's worth it for the flexibility.

Or sometimes gladly 0.5-1.0% of the principal sum, which is 1500 to 3000 euros for 300 TEUR. Is it then still worth it to you?

In any case, request written information about this from the respective bank before signing the contract.