Is single earner construction financing possible? Is equity available?

I wouldn’t have thought that, according to your opinions, financing could become tight after all. I assumed I would repay until the age of 65. I am currently 31 years old. It should be doable with a payment of about €1100-1200. After all, we are also bringing €300,000 of equity. That would put us at a loan-to-value ratio under 65%.

Since we are searching in the Frankfurt area and surroundings, the prices (between €600k-800k) are accordingly high. So far, I haven’t had any talks with banks.

If my wife starts working again, about €3000-5000 p.a. as annual special payment are planned.

3500 euros minus 1100 euros rent leaves only 2400 euros - that all goes away with 2 kids, right?

"At your age"? Did I miss how old the OP and his wife are?

I don't necessarily find that "relaxed" without having more information.

This is once again a typical forum prejudice.
A lot of gifted equity shows up and suddenly a healthy attitude towards money is assumed by some here.

I think finding a property for a family of four in FFM and the surrounding area for 600k will already be difficult. (Including necessary renovation work)
With every 50k that the whole project gets more expensive, the financing gets tighter.

If the OP ends up with a monthly burden of 1500 including incidental costs, I don't find that so relaxed anymore for him and the family.
You personally have to calculate 2000 to live on.
Depending on the property, sooner or later costs will come that you as a tenant simply don't have to plan for.