Slope position - Is a basement cost-effective?

Hello everyone,

We are currently planning our single-family house on a (slight?) slope and originally wanted to accommodate a granny flat + utility room and hobby room/office in the basement.
We had already concluded in another thread that despite doing some work ourselves, we might not stay within budget or the cost risk rises significantly if we build a basement apartment.
The planner we have since visited on site more or less confirmed this to us, but understandably cannot give us any concrete costs for the basement that we would need to plan for at the moment due to the current situation. The planner’s recommendation from a cost perspective is to forgo the basement, to plan the house slightly larger for the utility room + office, and to work with strip foundations because of the slope.

However, if I now build the house a bit larger and need strip foundations, that also involves costs. If the basement ultimately costs "only" 50k more than the other solution, then the cost/benefit ratio seems to lean towards the basement.

Since we now have to decide on the plan whether with or without the basement, I would like to hear your opinion on this. Perhaps you also have tips on how the cost difference to the basement can already be estimated reasonably at this stage?

The slope is marked in the picture as a red arrow, running evenly across the plot.
The plot/driveway/house entrance should be at street level (i.e. 2m higher).

The development plan can be found with the big search engine under "Einbeziehungssatzung_Gossersdorf_Flnr453_Textteil".

I would always build with a basement if you can afford it financially. Especially if it can partly be used as a living basement.