I answer questions that have no answer because this question remains open in many forums. fully functional in MyCloud EX2 and MyCloud EX2 Ultra 2-bay NAS devices. I've tried JBOD, Spanning, RAID0, RAID1 and they all work as expected depending on the configuration chosen. For my final configuration, I personally use two WD RED 1TB SSD NAS in RAID0 for better performance and then use rotating USB disk backups for any failures/recoveries that may occur. I've also experimented with other brands of SSDs with no success. If you really need SSDs in your MyCloud EX2 or EX2 Ultra then I would recommend getting the official WD RED SSD NAS drives as these are the only SSDs I personally think will work.
Kingston A400 240GB SATA SA400S37/240G solid state drive
60 Review
ADATA SU800 256GB SSD: High Speed Read & Write, 3D-NAND, SATA III, 560MB/s & 520MB/s
27 Review
Adata XPG SX8200 Pro 1TB NVMe SSD with 3D NAND, Gen3x4 PCIe M.2 2280, R/W 3500/3000MB/s (ASX8200PNP-1TT-C)
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GIGABYTE SSD 240GB GP-GSTFS31240GNTD: Boost Performance with Lightning-Fast Storage
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8TB Seagate Backup Plus Hub Desktop Hard Drive with Data Recovery Services
56 Review
Shock-Resistant Transcend StoreJet 25M3 USB 3.1 Slim Portable Hard Drive with 500GB Capacity
99 Review
2 TB External HDD ADATA DashDrive Durable HD650, USB 3.2 Gen 1, Blue
55 Review
18 TB External HDD Western Digital WD Elements Desktop, USB 3.0, black
95 Review