Financing consultant wanted

So, I’ll try to present the conditions here..:
In advance:
Current household net income approx. €3,100, 3 people (1 toddler), 2 cars, no ongoing loans/debts or similar
My price expectation for the house is €250,000. In addition, there are acquisition incidental costs - approx. €17,500. No equity is available. As collateral, one "could" specify the parental house.

Financing offer Bank (not a customer, newly met):
The bank calculated the financing with €270,000. Without equity, this would basically not have been possible. As a security amount, the parental house was considered with €50,000.
Now to the financing components:
Special credit program:
Amount €100,000, nominal interest rate: 0.85%, effective annual interest rate: 1.27%, fixed interest period: 10 years, monthly payment: €320.83
L-Bank Living with Child Program:
Amount €50,000, nominal interest rate: 1.30%, effective annual interest rate: 1.33%, fixed interest period: 10 years, monthly payment: €151.69
BFL Fixed Home Loan (I):
Amount €120,000, nominal interest rate: 1.60%, effective annual interest rate: 1.64%, fixed interest period: 10 years, monthly payment: €410.00
Total: amount: €270,000, monthly payment: €882.52

Financing offer Building Society (customer for over 10 years):
This is interesting. A quick inquiry at that time showed that I could easily get a loan. After the official loan application, my advisor presented the offer/offers to me. He said that the inquiry by a certain "Anchor Bank" (from which a certain percentage is financed) was rejected. However, the building society said that I am a long-standing, loyal customer and therefore (exceptionally) receive 100% financing. However, max. €250,000. I have to pay the acquisition incidental costs myself or acquire the house cheaper. It was also emphasized to me that I do not have to worry about interest rate changes and that the financing is planned through to the end. An amount I pay monthly until I am debt-free in contrast to bank offers where I have to take care of the follow-up financing, etc.

Here are the key data for 100% financing:
Phase 1 (savings phase)
Contract amount: €250,000
Available amount: €243,500
Interest rate: 2.93% (with 20% equity: 2.43%)
Effective interest rate: 3.07% (with 20% equity: 2.56%)
Total effective interest: 3.62% (with 20% equity: 3.09%)
Fixed term: 180 months
Monthly interest payment: €610.42 (with 20% equity: €506.25)
Building society tariff: (I won’t specify it, so the provider is not revealed)
Building society sum: €250,000
Monthly savings rate: €533.00
Credit interest rate: 0.50%
Balance after 15 years: €99,202.98
Loan entitlement after 15 years: €150,797.02

Phase 2 (repayment phase)
Monthly interest and repayment rate for the building society loan: €1,143.42 (with 20% equity: €1,039.25)
Nominal interest rate: 2.74%
Effective interest rate: 3.09% (with 20% equity: 3.06%)
Building society loan term: 157 months (with 20% equity: 177 months)

That was a lot of information now. I hope I was able to present everything clearly and comprehensively enough. Finally, I have to mention that I only consider the collateral with the parental house as optional. Of course, I would prefer if the parental house had nothing to do with the matter.

I hope you can better assess the conditions and give me some recommendations on which financing would be advisable for me. Maybe neither financing makes sense?

Many thanks in advance!

Best regards from Baden!

Building savings contract and loan are always difficult to compare. I am currently dealing with this as well. The problem with the building savings contract is that in the first 15 years you only pay interest on the building loan without any repayment. In this case, it is €610 x 12 months x 15 years = €109,800. And that without any repayment having been made. However, with the building savings contract, you have interest rate security over the entire term, which you of course have to pay for. In comparison to the annuity loan, after 10 years you have a remaining debt of €198,000 and have paid €33,000 in interest. However, you do not know what the interest rates will be in 10 years. If they are at 5%, it will be very difficult. Therefore, it is worth considering whether to choose a longer fixed interest period and/or increase the rate.

Hello and thank you very much for your assessment! Are there perhaps other specialists in the forum or people with experience?

I would be very grateful for your opinions!

Thank you in advance and best regards