Idea generation, avoiding slipping despite the slope?

That is not possible on the property. Too steep. Draw it on mm paper, then you will see the misery.

Fill up 3 meters This is 1 entire floor I would never subject myself to such a steep driveway. It's somewhat like at my parents' place. Falling is inevitable My parents curse every winter. Filling up in height causes insane costs. If bungalow then different property On the property, I would work with a basement. Depending on restrictions and budget, plan for stair lift, platform lift, or elevator

The higher part is about 3 meters

Would you even get approval for such a fill?

So, the OP has a mobility limitation, the progression of which he expects, and therefore wants to live on a single level; the building envelope is 20 m from the street at the rear end; the 3.5 m height difference (slope ?) refers to this distance ?; but otherwise: are we talking about a potential plot or is it already purchased, ... ?

A bungalow like ours measures 13.5 by 10. You really have to draw it to the mm or on graph paper to see what works and what doesn’t. I stick to my opinion, it will be difficult.

So, the OP has a mobility restriction, the progression of which he expects, and therefore wants to live on a single level; the building window is 20 m from the street at the rear end; the 3.5 m height difference (slope?) refers to this distance?; but otherwise: are we talking about a possible plot or has it already been purchased, ... ?

How severe is the restriction or how severe will it be. There are affordable options to overcome the stairs

The fundamental question is
Is he allowed to build a bungalow
Will the filling be approved
What about the driveway in winter? Clearing and gritting.

Does he only want to leave his property by car?