natural garden / flower meadow / lawn

Hello, I am currently facing the difficult question of how to proceed with our garden. The property is over 1100 sqm, so let's say about 800 sqm behind the house. My dream has always been a natural garden with a pond, woodpile, flower meadow, stone wall, etc. At the moment, it’s a bumpy track with all kinds of plants, unfortunately including nettles, thistles, blackberries, ragwort, where ticks and possibly grass mites also feel comfortable. In addition, it looks a bit shabby next to the sterile neighboring gardens.

My brother-in-law would like to level everything with the mini excavator, spread topsoil, and sow lawn. This would have the advantage that my children could also play football, camp, or do other things there.
The only access at the moment is through the garage; garage doors will be installed soon, then no excavator will get into the garden anymore...
The drawbacks would be the costs, especially for the topsoil (unfortunately money is all gone), all the dirt (would first have to be unloaded in front of the house), and the work (countless wheelbarrows to load, drive behind the house, and spread there).

Has anyone here realized a natural garden? Would you do it again?

Here is a photo, the garden slopes down to the left and towards the back.

Hello,
my property is about 1500sqm. Of that, about 100sqm is lawn. I leave the rest to itself. I only occasionally drive the lawnmower through the middle so you can walk through there. I also sowed seeds for a flower meadow to specifically do something for the bees.

Gradually, I want to enhance the 'Areal der Natur' with this or that: small bird pond, larger stone collection for lizards, wooden frames for insects, etc.

The advantage is that for grilling and sunbathing you use the lawn area, and for a good feeling the eco area. But beware, my experience also shows that the 'Öko Bereich' requires its maintenance time, although less than the lawn.

here again a detailed image from the 'Dschungelberreich' that doesn't really come across from the overview image.