Verdict

Both are comparable SSDs. The ZA4000NM1A002 is rated for more write endurance than the WDS400T2R0A, so it's the longer-lasting choice for a NAS that sees steady writes; for light use either is fine and price decides.

WDS400T2R0A ZA4000NM1A002
Capacity 4 TB 4 TB
Form factor 2.5 2.5
Interface SATA SATA
NAND type TLC TLC
Endurance (TBW) 2,500 TB 5,600 TB
DWPD - 0.7
DRAM cache Yes Yes
Power-loss protection No No
Sustained write - -
Price / TB $212.50 -

Highlighted cells mark the stronger spec for a NAS build. Failure rates from Backblaze Drive Stats where available; $/TB uses the cheapest live price where available.