I have to agree with the other commenters.
The Lenovo Z6 Pro has been found to have a great camera, not quite as good as the LG G8 or Samsung S10+ or even the Huawei P30 Pro.... but in the ballpark as the OnePlus 7 Pro.
So either DxOMark bought a unit from a third-party vendor which has a hacked-global-rom.
Or the scores have been adultered to meet a purpose. Or both.
As an added bonus, the Lenovo Z6/Youth/Pro are running a Stockish-OS and using traditional Sony Exmor sensors, like the famous IMX 586. This means flashing the Gcam MOD can essentially boost the performance of the Z6 Pro's camera close to that of the Pixel 3XL and Sony Xperia 1.
After the OP7 Pro scandal, OnePlus lost any leftover credibility it may have retained before.
For a $400-$500 phone, the Z6 Pro has a pretty decent camera setup.