Which option is smarter for buying an existing building without equity

Good day,

we are planning to settle in the Uckermark and to purchase a fantastic house built in 1920 and fully modernized in 2008 (roof, windows, water-guided fireplace, underfloor heating, fitted kitchen, new bathrooms, etc.).

About us:
Me, married, 32, net income: 2,200, permanent contract.

Wife, net income: 2,000, permanent contract.

Both still childless.
But hopefully this will change by next year.

No equity for financing available.

I already have an existing mortgage.
(Approx. 82K taken out in 2013, now 62K left. 3.5% 32k R+V, 2.55% 50k KFW, fixed interest rate 10 years)
It is serviced with 477 euros.
I bought the house for my mother (55 years old).
She takes over all costs there.
I have no expenses there.

Otherwise, there are no other liabilities.
Our current rent in Berlin is 1,450€.

Now about our new house.
Total financing requirement:
199,000 euros

Offer 1 R+V:
50k over KFW at 1.55%, 10 years fixed interest
Installment: 208€

149k over R+V / Schwäbisch Hall building society saver with 2.4%, after 13 years (or maybe fewer years due to special repayments), it will be 2.15% for the next 10 years. Then everything should be paid off.
The building society saver probably costs a one-time fee of 1,654€, which will be charged via the installment over the 10 years.
Installment: 740€

Total: 948€

Option 2 via Interhyp:
BHW: 106K with 1.50%
Installment: 382.50€
Hanseatic: 43,000 with 5.89%
Installment: 359.65€
KFW: 55k with 1.55%
Installment: 208€

All with 10 years fixed interest.
With Hanseatic we can repay the entire loan at any time through special repayments.
At BHW, special repayments of up to 5,100 € per year are possible.

Both options cost about 37K after the first 10 years.

Since we are completely inexperienced, we would appreciate an assessment of the options.
Thank you very much.

Hello! That means you are currently spending €4,200 per month! No equity whatsoever??? The house that belongs to you is basically being maintained by Mom. Basically, I would send an expert into a house built in 1920! Renovations from 2008 may no longer be valid. Then you should choose a 15-year fixed interest period at this interest rate level if you are going full financing. How about further costs like mobility to Berlin! Good luck, I am skeptical.

Somehow I don't quite understand the setup.

The existing house is rented to your mother, and you have income from [V&V], right?
Then for the existing loan, only 20k, i.e. 4k per year, will be repaid in 5 years? And the existing 50k from the [KfW], is that bullet repayment?

And then 66% of a net salary is due for rent.
I couldn't even manage that with a financing...

Well, okay, everyone as they like. But I would first think about my claims and expenditure situation. Then urgently about family planning and how that will be paid for. Children cost money and a salary will also be lower.

And, as already written, have an expert take a look at the place and see what additional costs might occur.

I wouldn't give you money for the project. You are already barely managing. There is hardly any room for special repayments or building a security for the loan volume after 10 years. That can end badly if even a small thing happens.

Or maybe I just don't understand the construct and am overly cautious?