OP, youve been taken for a ride by paying for a dpc report by a dpc contractor. The surveyor, presumably the home inspector, who advised you is possibly getting a back hander from the dpc co. thats how it works.
There are independent paid dpc surveyors, not many but they are out there.
The dpc co. by asking you to get a landscaper then if anything goes bad with their work they can blame you and your landscaper. Any builder or diyer can lower that backyard, no need for landscapers.
You with a few trades or using a local builder could do that work, inside or outside.
Whoever came out and did the dpc survey was probly a sales person not a contractor. Read the stories below.
Theres lots of free damp and timber surveyors advertised most place. a lot of them might be rubbish but they are free.
No such thing as good reviews on those paid for sites, the reviews are all fake. You possibly used a paid for trades kind of site.
nothing to stop you from buying the place maybe you get a price dropbased on the report.