Which garage floor is suitable for contamination?

Thank you. I am now also leaning towards this type of floor (so no screed or something similar). Regarding abrasion (car tires, dropped tools...), I think this floor should also be fine. Regarding the formwork, I will talk to the construction company again to have them pour the floor only up to the inner edge of the exterior wall (garage driveway). The formwork is already in place. However, it should not be a problem to attach additional planks or beams 5m wide (gate width) from the inside onto the existing formwork, which are as wide as the masonry. (The masonry is 24cm). At this point (meaning the inner edge) they also place a finishing rail, on which the sectional door then runs.

there is liquid PVC or "garage coating" in a bucket. check at norma. you paint it on the floor and it is oil resistant.

You can completely forget that. You will be patching it every year. That only works on screed because you can't pour concrete that cleanly. And don't forget the slope when pouring concrete!

Hello questioner.
After the above "answers" you will probably continue to look at your construction site with questions, as I suspect.
However, your questions can be answered as follows:
If the garage floor has been concreted, it actually does not need any further bonded screed.
So you can save the additional 50mm build-up height. However, it depends on whether the concrete surface was well rubbed/smoothed or delivered with a "broom finish."
In the latter case, it would be more complicated, since a bonded screed should be applied.
The advice from the construction company addressed to you is correct that the later surface of the garage floor must be protected! Whether with or without bonded screed.
That means the surface is ground, vacuumed, primed, and coated with, for example, a largely abrasion-resistant concrete paint. That would at least be a cost-effective option.
Regarding question 2 (closing profile):
This can definitely be useful (better: recommended) as an angle profile! It protects the concrete or screed edge from damage caused by mechanical loads. The profile is available in stainless steel versions and is glued to the concrete or screed surface after strip-like priming with a synthetic resin.
This also provides a visually neat finish, which is not always guaranteed when formwork is removed (for working on concrete or screed).
I would casually call this position "pennies," which can prevent greater damage.
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I hope to have contributed a little to clarification.
Regards: KlaRa