Installation of the wastewater pipeline for new construction

Hello,
I am new here and as a "construction woman" not very technically knowledgeable. I am glad to have found this forum.
Tomorrow is supposed to be the first appointment at the construction site. I am building a bungalow without a basement with Heinz von Heiden, so almost everything from one source.
The site conditions are such that the construction road and future driveway have to go next to the house up to the neighbor's boundary. Minus the foundation cushion around the house, there is about 3.50 meters of width available.
Now the excavator of the subcontracted company by the general contractor has made an offer for the construction road in full width. However, between the foundation cushion and the construction road, the wastewater pipes (sewage water as well as rainwater) still have to be laid.
The excavator offered these works in an additional offer for over €10,000!!!
We are talking about about 40 meters of trench length...
Execution by him is therefore out of the question. Now I have a company that does this at a reasonable price.
My question.
At what stage in the house construction schedule are the drainage pipes laid?
Is it sensible to do this before securing the construction road and thus before the foundation slab is made? This with the background that then the construction road does not have to be reopened again. Is this technically even feasible since no pipes from the house/foundation slab are laid yet? And can two companies even work in parallel next to each other?
Or do you leave a 50 cm strip "free" between the foundation cushion and the construction road (which would then be only 3 meters wide) so that it can be dug up later and the wastewater pipes laid? I do not want to spend money twice and break up the compacted construction road afterward.
The excavator does not care. The more volume, the more profit.
It is similar with the securing at the side of the construction road to the neighbor. I want to have L-bricks set exactly on the boundary because I am somewhat lower than the neighbor; in addition, the fence is to be mounted on them. For me, it makes sense that the bricks are set before the construction road is compacted and filled. The excavator has no idea; he is more for the rough work... So two companies would have to work there as well...
Thanks for your quick tips so that I can join the conversation tomorrow afternoon.

Attached the drainage and site plan

Hello brave woman! It generally concerns all the utilities located in the outdoor areas. So drinking water, electricity, telecommunications, as well as wastewater and rainwater. The drainage goes into a combined sewer in your case, so it is merged. These civil engineering services are carried out once the house is standing and the scaffolding is gone. It then makes sense to do everything with one civil engineering company. The process is that the final interior finishing takes place and outside there is space for the civil engineer to work, who will surely also install the parking spaces. I had an almost identical situation last year, what a coincidence. Good luck with your project.

Thank you for your answer. So then to dig up the constructed and 40 cm compacted construction road along the house again? VG

These works were offered by the civil engineer in an additional offer for over €10,000!!!

Wow!

We are talking about about 40 meters of trench length...

Oh, I see.

At what point in the house construction schedule are the drainage pipes installed?

Later. Then, when all toilet drains are fixed according to the drainage plan and the gutters are installed. Only then does the excavation of the drainage begin.

How far apart are the providers in terms of price?

I would not remove anything from the contract as long as Heinz von Heiden is on the logo. Warranty etc.

8000,-€ !!!