Financing completed - is the interest rate good?

Sounds good to me too. You just have to follow through with the Sondertilgung! But I’m not worried about that. After all, you have also saved up good equity (land).

Be happy, we have a 2.3% mixed interest rate for the first 10 years.

Having this discussion now is more philosophical than meaningful.

I don't see it that way, philosophical doesn't have to mean senseless. Even if for the OP "the train seems to have left," it helps others who are currently dealing with it as input. But even for the OP, confirmation or, if you will, praise (well done) can be motivating.

@OP:

Reads consistent. We have similar conditions, property as equity, currently parental leave, and will have to finalize our financing soon. Therefore, I gladly take your post as input. Thanks.

See it this way: the further the interest rates decrease over the term, the higher the chances of an increase in the property's value. We concluded similar amounts a few months ago at 1.9. Every interest rate cut results in more money on the market, so you can find something positive in any development!

I don’t see it that way, philosophical doesn’t have to mean meaningless. Even if for the OP "the train seems to have left the station," it helps others who are currently dealing with it as input. But even for the OP, a confirmation or, from my side, praise (well done) can be motivating.

For the questioner, it’s not particularly great either if he now finds out that he could have come out significantly better. It’s some kind of fairy tale that the prices offered online do not also apply if you go there. If the bank advertises €100,000 at 1% with 50% loan-to-value ratio, then this 1% is also available (or better) — or none at all if the bank refuses. But what arguments should the bank have to worsen its offer? Collateral? That was already clearly specified beforehand? Creditworthiness? Either one is creditworthy or not. Default risks are already factored in via the loan-to-value and interest rates. We went through loan inquiries last year and experienced that NO bank gave a worse offer than what they advertised online/flyers etc.
And regarding the interest rate: more important than the last few decimal points after the comma is the general approach to handling the transaction. We were offered 1.9% over 25 years at the Allianz, but they wanted invoice copies for every €5 bill from the authority, exact payment schedules, and above all that the money then be transferred directly to the construction company with delays (the dunning fees, of course, remain with the contract partner, so with yourself...). We then decided to conclude with the local Sparkasse, which only wanted €200,000 to be documented out of our €270,000 loan (which exactly corresponded to the house price at the construction company – so I only had to send the Sparkasse the installment invoices by email). The money was transferred to our own account and I could pay every invoice myself. The remaining €70,000 could then also be freely spent somehow in the house for samples, kitchen, outdoor facilities, incidental construction costs etc. We found this way of placing trust in us very decent. In the end, after moving in, the broker stopped by briefly and wanted a few documents (cadastral survey plan, confirmation from the construction company that everything was paid, and some little stuff...) and then he was gone. If we now always pay punctually, we will not see each other again for 20 years.

for the questioner, it is not particularly great either if he now finds out that he could have come out significantly better.

Why not, with such a decision you have to know the facts and not give in to any fairy tales.

And who knows, maybe the financing is fresh and you could have asked again.

and about the interest rate: more important than the last few decimal points behind the comma is the general handling of the process. ...we then decided to conclude at the local Sparkasse, ...

I’m 100% with you there. We also won’t compare extensively or negotiate to two decimal places. It’s always trust and the overall package that matter just as much. I’ve been a customer at my Sparkasse for 25 years. One call and things are settled quickly via the short service route. Almost everything is done by phone, online, or email. We have set up a separate “construction account,” through which the entire house construction runs. The bank advisor only has to go into the system and has my/our complete history. Despite the current tight household situation (wife is the main earner and currently on parental leave), we save 1,000 euros per month and except for one insurance and two savings contracts for godchildren, we have zero expenses on my checking account.
In addition, we will certainly get 12 months of free commitment fees and also do not expect any hidden or expensive additional service costs.

But as I said, this will hopefully become clear very soon.