These prices seem exorbitant.
I've built a similar home backup server for $1700, Dual 10core Xeon, 32gb ECC ram, 32TB + Parity Protected Array and throw in a 10gbe or SFP+ port for $100 more.
If these are WD Blacks (7200rpm) they are $179 for 4TB*8 = 32TB, $1,432.
For $12,000 I would expect an all-ssd machine.
Individual SSDs this past black friday are now below $150 per 1TB. $150*32 = 4,800.
Throw in an optane 905P for $1,200 for a cache disk and you've got an insane local SAN.
Then again is the software worth doubling the margin?