Takes over 10min to copy a couplle of hundred megabytes to the R6 from my MBP 16", was the same storry with my MBP 15".
R6 is in raid5 and i have 6 TOSHIBA DT01ACA2 Drives. All system statuses are OK in Promise Utility.
The R6 is plugged in directly to my MBP with an original TB3 to TB2 dongle from Aplle and i have nothing daisy chained.
My computer spec is: MacBook Pro (16-inch, 2019), 2TB ssd, 2,4 GHz 8-Core Intel Core i9, 32 GB 2667 MHz DDR4, AMD Radeon Pro 5500M 8 GB Intel UHD Graphics 630 1536 MB,