8Tb HDD's work for sure. I installed a WD Red in my brother-in-law's Q10Pro last year and it has worked fine, with no issues.
When I set it up, I did use the rear USB 3.0 plug with a cable into my PC and partitioned/formatted it like any external HDD. As long as the drive was partitioned in Windows 10 using Computer Management, with GPT and formatted NTFS, it should just work. If other software was used to partition and format the HDD, there could be a compatibility issue.