ᐅ Prefabricated Garage 6 x 6 Meters Supplier

Hello.
We are looking for a supplier of precast concrete garages as a large single garage with one door.
Has anyone here had such a garage built or installed?
Which supplier did you use? What were the costs?
So far, we have shortlisted two "affordable" companies with quotes around 16,000 euros each. Three other quotes range from 18,000 to 25,000 euros.
We want one door with two remote controls, an electrical package with several sockets, two light fixtures, no door and no window. Everything in white. Roof coating, sectional door, M-rib Woodgrain finish, automatic door opener, and drainage included. Delivery and installation on strip foundations supplied by us.
Looking forward to tips and recommendations...
Have a nice evening...

We receive similar items from the company Rekers.

I would reconsider the part about the window, at least. This window could be opened if needed (high humidity in the garage), allowing moisture to escape outside. Also, having a door to get quickly from the garden into the garage is sometimes quite practical, especially if you store some garden tools or outdoor furniture in the garage.

Hello garden enthusiast... The garage will be partially backfilled with soil at the rear and partly on the side... (slightly sloped plot). Therefore, no window or door there.
Hello bieber... our most affordable offer is also from rekers...
Anyone else who has had experience?

I'll join in here—if anyone has an offer, I would also like to get information about the manufacturer.

Our Kemmler model is 6x6 meters (20x20 feet) with extensive green roofing of 10cm (4 inches), an anthracite sectional door, one window, one door, electrical and lighting with wall connection to the neighboring garage, unplastered, built on an existing basement for €20,500.