With the right preparation equipment and self leveling concrete mix you will be able to do this job yourself in 1 2 days.
Floor concrete leveling machine.
With this you would avoid common problems associated with concrete floors such as high spots and unevenness.
It spreads across uneven slabs filling in low spots as it creates a new level surface.
For an uneven floor grinding the concrete floor high spots is your only option.
If you plan on leveling a concrete floor you can do so with relative ease by using a leveling compound.
Although this sounds simple this requires a great level of skill and equipment.
Leveling concrete using grinding.