Connection concrete staircase / UB alternatives to expansion joint, experiences?

Hello dear forum,

we are building with a developer from Lampertheim and are surprised by the following situation.

We have a basement and a concrete staircase. This was placed with the last step (below screed level) on the ground slab of the ground floor. Now the construction has progressed and the topic of floor coverings came up, and we were told that we are entirely responsible for leveling the stairs. The problem now is that our hallway is not uniformly tiled, and the grout pattern would be interrupted by a necessary expansion joint (format of the basement staircase riser). We definitely want to avoid this because it ruins the entire grout pattern in the entrance area.

Are there possibilities, for example through a decoupling mat, to bypass this expansion joint between the staircase and the screed?

I have uploaded a few pictures for clarification.

I apologize in advance for the imprecise description but hope at the same time that our problem is understandable. We also hope that someone from the forum can share some useful experiences in this regard.

PS: The step that protrudes into the hallway was not shown on our construction plans. When the step was visible in the shell construction, we assumed it would be covered by the screed (we are total laymen and lack experience).

Many thanks in advance!

we are building with a developer from Lampertheim and are surprised by the following situation.
We have a basement and a concrete staircase. This was placed with the last step (below screed level) on the ground slab of the ground floor. Now the construction is advanced and the topic of floor coverings came up, and we were told that we are fully responsible for the leveling of the stairs. The problem now is that our hallway is not uniformly tiled, and the joint pattern would be interrupted by a required expansion joint (format of the riser of the basement stairs). We definitely want to avoid this because it would ruin the entire joint pattern in the entrance area.

You cannot build with a developer, but only buy from one. You would build with a general contractor, but you probably have a developer here. It is just the case that a joint pattern cannot be the top priority. However, it is also unusual that the buyer would be responsible for the tiling here (???). With the construction involving the shift of the stairs onto a lateral step into the ground floor, it is hardly possible otherwise. I would recommend tiling this top step in continuation of the surrounding joint pattern and executing the expansion joint in a slightly contrasting colored material. Perhaps might have some technical input on this (?)