I got my enterprise SSDs (1.6TB, 3DWPD, drawback: SAS3) from our Craigslist-equivalent. First I got 2 for 150€ and had a nice chat with the seller, who seems to had a big box of these. A week later he offered me his remaining 3 disks for another 150€. On eBay it seems you have to make offers.
Some local info: I also noticed on the German eBay getting Chinese cards to be much more expensive than on eBay in the US. The same seller asking 80€ or 100€ for the same LSI 9400. However, finding the article on eBay.com and then using the item ID on eBay.de allowed me to get it for the better price.
How do you find them, please? Do you just query for "enterprise ssd"? I've just run this search and indeed it returns lots of models from different brands. Thank you.
https://forum.level1techs.com/t/all-sk-hynix-p41-ssds-suffer...
You'll find reports from around the web of people flashing updated firmware and getting better performance for a few days or weeks, then it cuts back in half again.
I have a 10 year old Intel one in one of my machines and it's still 95% health.