That seems reasonable, I don't buy NAS for datacenters (just run a modest 80tb one for my home lab) but equivalent rackmount 16-bay ones from other vendors would be more expensive (maybe $5k-6k?) and with less polish.
I laughed.
https://kb.synology.com/en-us/DSM/tutorial/Why_does_my_Synol...
https://www.bhphotovideo.com/c/product/1618911-REG/synology_...