Which loan is for house construction?

Much more interesting than the number of people who build is the number who are still living there after 15 years

You really have to be able and willing to afford it. Rent is not bad per se. You can actually save a lot of money here too. Because under normal circumstances, you won’t get back the purchase price of the property. Especially not if it was financed.
The real financial advantage lies in rent-free living in old age. But if I were to set aside €600 a month now, which is the amount that the house costs us more than renting, I would have saved a nice sum in 20 years.
So you don’t have to jump into it.

15 - 20 TEUR is probably really too little. The annoying thing is, the actually cheap direct financers become really expensive. We were surprised at what kind of favorable conditions we were offered for a long-term loan at a Raiffeisenbank. 3.3% with a 30-year term. But that only works if you get > 20% equity together, maybe you can manage that through personal effort. The 3,800 EUR net should definitely be enough for the banks!

Just follow nordanney's suggestion and save 1000EUR/month from now on. You should have that anyway to be able to manage a house. This way, you can be more relaxed knowing that you can handle a house and its ongoing costs. The 50TEUR equity is already a good start.