How much equity you use is up to you. The more, the better the interest rates. However, you must also consider that the bank will require that the equity be used up first.
I would recommend paying for the property with the equity, then you would have time to properly plan your house, to check what you can actually afford (& what you cannot) and you can calculate everything correctly.
Still continue at a similar pace and keep an eye on the interest rates.
From now on, any further hasty reaction can financially ruin you or at least put you in a much worse position.
Good luck and continue to use the experience here from the forum
Yes, I will think everything through thoroughly. I also have many people in my environment who have built or are currently building. I will get tips from everywhere. Of course, I will keep you updated here
the project is finished. I built a 4-family house (1 apartment in the basement, 1 apartment on the ground floor, and 2 identical ones on the upper floor).
I have two tenants and my mother in the house, the ground floor belongs entirely to me (175 sqm with hobby room, etc.), the basement has just under 50 sqm and the apartments on the upper floor have about 72 sqm including balcony.