Earthworks for supply lines / construction road and garage

Hello dear house building forum,

I have a small concern: we already have two quotes regarding supply lines (the connections are all already on the property) to be laid up to the not yet built house and to create a construction road as well as the excavation of a garage. However, the supply lines would have to be laid on the left at the property boundary and the construction road on the right (because of the future driveway to the house), so you can't save any excavator digging here. The laying path of the supply lines would be about 50m and the construction road is 25m. In addition, there is the excavation (no foundation slab) of the garage 6m*9m. The quotes are each around 40k€. I actually find that a bit expensive..

My question here is, can a layperson possibly do this themselves? I don't know if I am imagining it too simply, but for the supply lines you basically only have to dig a trench, put in the empty pipes + channel, fill up with sand/gravel and then put the excavated soil back on; the slope is already included for us, as the property is on a slight incline. Construction road is similar, remove soil and fill up with gravel. Then there is the garage :)

My approaches would be as follows:

[*]rent an excavator yourself and find out how it should be done. Problem: I still can't operate an excavator and don't really know how everything should be done.
[*]rent an excavator with an excavator operator
[*]possibly obtain further counter offers

How would you proceed here to save some money?

Thank you very much for your help!

When measuring the length, be sure to strictly adhere to the sewage slope, otherwise the drain cleaning service will become your friend, in principle all pipes can go into one trench. I would get additional offers.

two offers for supply lines (the connections are all already on the property) to be laid up to the not yet built house and to create a construction road

What is included in the offer? What happens with the excavated soil? Creating a construction road… does that already include gravel? 25 m of construction road and garage excavation are not small quantities.