Opinion on our financing in Berlin

Hello, I wanted to hear your opinion here. We, both 36 + one child, want to buy a good used house built in 1996 in a popular location near Berlin. Overall, costs of 447,000 euros will be incurred. We have about 125,000 equity. So 321,000 euros remain to be financed. We are thinking of a rate of 1400 to 1500 per month. This should be financed from 2 times Wohnriester, an existing building savings contract, and an annuity loan. We want to be finished by 2040, so in about 25 years, then we will both be 61. Currently, we have 2400 net + 1600 net (due to part-time), so 4000 net available. Operating costs of the property are about 350 euros, so roughly estimated, housing costs are about 1800-1900 euros per month. That leaves us just under 2000 for everything else. We want another child, so part-time will probably remain for a while with the second salary. Opinions? Realistic? Tight? Pitfalls?

The Wohnriester is, in my opinion, a trap. How well are you informed about the consequences?

How high were the renovation costs estimated?

Hello, I also had an annuity loan offered to me. Perhaps KFW programs can also be used sensibly

Have you already received offers for the financing examples? How it is supposed to proceed and under what conditions? Without this information, an initial rough assessment will be difficult.
As already written, note the Riester topic in old age, note "Wohnförderkonto".
Furthermore, I would include a low Kfw loan if possible.
But I think a few data are still missing here.

Furthermore, I would include a low KFW loan if possible.

There will be no KFW subsidy solely for the purchase of a used house.

There will be no KFW subsidy only for the purchase of a used house.

And what about the KFW home ownership program? I don't know what the current interest rate is there now, but that also varies here with the fixed interest period, etc. But as far as I know, you can also get this when purchasing existing properties.