ᐅ Pouring a concrete landing

Hello,

I still need to pour a concrete platform at my front door (38 cm (15 inches) high, plus an additional 12.5 cm (5 inches) for a step).

At the front door, I have a door frame extension.
If I pour concrete up to the door frame extension, will it withstand the pressure from the concrete without warping (there is nothing on the outside yet), or do I need to install insulation strips like those used under screed?

In my case, the front door is 78 cm (31 inches) higher than the first step in the staircase.
Now a platform is to be placed there.
The ground floor has already been fully flame-cleaned,
but I think if I screw rebar into the wall and the stairs and place two steel reinforcement meshes into the concrete layer, there shouldn’t be any problem, right?

And if I pour the first platform at 38 cm (15 inches)
and then add another 12.5 cm (5 inches) on top,
it should fit exactly, correct?

There should be no insulation strip between the concrete and the wall, right?

And if the concrete is 2 cm (0.8 inches) below the door threshold height, it will still fit perfectly once I lay tiles on top, right?

Thanks, regards