Looking for ideas for a construction staircase.

Hello,
the following situation:
The shell is just finished and the roof is covered.
I have two floors to overcome. The first staircase already exists, as it is a concrete staircase. The second staircase, which runs above the first, is only temporarily built. A formwork was also made for this, as originally a concrete staircase was supposed to be made there as well. However, I have decided at short notice to install a wooden stringer staircase without risers here, so that more light can come through.
Now the temporary structure must be removed, as the interior plasterer is coming.
What could I install now and how? I think the final staircase will come only after the screed?
Or could the staircase builder already install the final stringers now and only fit the steps with temporary treads, so that the screed and the rest can be done?
Every other temporary solution seems very elaborate to me?! Or is there something from, for example, scaffolders?

I simply built it myself out of planks. But of course, it wasn’t officially up to code. So if something had happened, I probably would have been responsible. You have to keep that in mind. Stair builders, carpenters (roofers) often already have ready-made construction stairs, which they then rent out for around 200 EUR or so.

Hello, the following initial situation: The shell is just finished and the roof is covered. I have to overcome two floors. The 1st staircase already exists, as it is a concrete staircase. The second staircase, which runs above the 1st one, is only provisionally made. Formwork was also done for it, as originally a concrete staircase was also supposed to be made there. But I have decided at short notice to install a wooden string staircase without risers here so that more light comes through. Now the provisional construction has to be removed because the interior plasterer is coming. What could I install now and how? I think the final staircase comes only after the screed? Or could the staircase builder already install the final strings now and only equip the steps with provisional treads so that the screed and the rest can be done? Any other provisional solution seems very elaborate to me?! Or is there something from, for example, scaffolders?

We had the same initial situation. In the closed shell, the wooden string staircase with wooden steps was installed before the interior work, all nicely wrapped with foil and on the tread steps, cut-to-size material that looked like furniture backs. Not a single scratch. I found this procedure very pleasant.