Screed finishing in a basement garage

Hello,

I had to build the garage into the house in my new construction.
The entire area under the garage is basemented, where the heating room and the pellet storage are located.
Since everything here is basemented, there is also perimeter insulation in the garage driveway.
I can't just pour the screed over it because the perimeter insulation compresses, and I'm afraid the screed will then break off.
The screed layer said it is enough if I simply pour a base in front of it, and he will then pull the screed right up to that.
But isn’t that a thermal bridge?
What is the best way to solve this problem?
And is it sensible to install insulation under the screed? And if yes, can Styrodur withstand being driven over by a car?
And do you pull the bitumen membrane, which I am supposed to lay here on the concrete slab, completely over it?

I have also drawn a sketch; I hope it makes things clearer...

What does the construction manager say?

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Thank you and

Regards Yvonne

Well, I'm basically the site manager myself.
I only had the shell and the roof truss done. I’m doing the rest step by step myself or together with companies as far as possible.
I completely outsourced the screed again. But the screed layer just said I should simply pour a base layer of concrete in front so that he can lay the screed on top.
But I think I’ve meanwhile understood what he means. At least I suspect that there’s a separation in the screed at the place where the garage door touches the floor. That means there are basically 2 screed slabs that no longer directly touch each other.
So that could be correct then, right?