Delivery of prefabricated garage - strip foundation on a slope - securing?

A company was commissioned for this, which consulted with the garage manufacturer.

Then I would contact the company and the garage manufacturer and tell them to settle it among themselves. That doesn’t really sound like your problem.

A company was commissioned for this, which consulted with the garage manufacturer. The foundations have also already been inspected and approved by the garage company.

I am utterly amazed.

The site extended exactly to the water tap (0.5m) before the last heavy rain washed away some soil.

Well, then you have already seen the truthfulness of my babble.

A berm is no use to me, as the delivery vehicle can no longer get close enough to the foundations and therefore cannot place the garage.

That it is supposed to be delivered from the valley side, I must have overlooked, but in my opinion that does not make it any better.
Document in writing all claims of involved experts that it will work that way (and that they are liable for this opinion).

Exactly, it is delivered from the valley side and then backfilled, resulting in a ramp from the road to the garage. Here is another picture for illustration.

Document in writing all claims by the involved experts that it will work this way (and that they are liable for this opinion).

The company that set the foundations no longer even responds to letters from a lawyer (but for reasons other than the foundation).
Therefore, I don’t see anything to gain from that. I will probably have to solve the problem myself.

I am also pessimistic about the garage vehicle. Then a 100-ton mobile crane will probably be needed after all.

Do you think it is sufficient to place compacted gravel about 3 meters in length up to the height of the bottom edge of the foundation strip (marked in blue) to (temporarily) sufficiently support the slope??

Here is another picture for illustration.

Wow, so the garage is not in front of a slope, but behind an incline. I was already wondering why it was supposed to be delivered from behind. I would wait until the driveway terrain is made - that is, the red dashed excavation is filled in - but not yet finally compacted and paved.

...I would wait until the area of the driveway is constructed – meaning the red dashed excavation is filled....

CURRENT condition (red dashed line): The garage vehicle could unload the garage, as it can drive up to 0.5 meters in front of the foundation.
BUT: The foundation would very likely break out.

Alternative (blue dashed line): It will be filled with gravel up to the street, which would stabilize the foundation again.
BUT: The garage vehicle only allows unloading of the garage with a slope of max. 1% incline! However, we have about ~14.5%.
->>> Therefore, an additional mobile crane (approx. 180 tons) would have to be rented, which lifts the prefabricated garage from the garage vehicle and places it from the street onto the foundations. -> expensive fun.
Therefore, I am considering whether to put 1.5m retaining wall panels in front of the foundation to support the slope. On top of that will later come the KFT layer and the surface. But is that enough?

The picture is funny. Was this method of transport planned by @goalkeepers mayor, or did you play a trick on me and I am now seen on hidden camera?