Not surprsing. Flash is for hot/warm storage, not for cold storage, but using literal bottom of the bargin-bin barrel no-name drives that are already highly worn really doesn't tell us anything. Even if these were new or in powered on systems for their whole life, I wouldn't have high confidence in their data retention, reliability or performance quite frankly. Granted, there is something to be said about using budget/used drives en masse and brute forcing your way to reliability/performance/capacity on a budget through shear scale, but that requires some finesse and understanding of storage array concepts, best-practices, systems and software. By no means beyond the skills of an average homelaber/HN reader if you're willing to spend a few hours of research, but importantly you would want to evaluate them as an array/bulk, not individually in that instance, else you lose context. That also typically requires a total monetary investment beyond what most homelabbers/consumers/prosumers are willing to invest even if the end-of-the-day TB/$ ratio ends up quite competitive.

There's also many many types of flash drives (well beyond just MLC/TLC/QLC), and there's a huge difference between no names, white labels, and budget ADATA's and the like, and an actual proper high end/enterprise SSD (and a whole spectrum in between). And No, 990/9100 Pro's from Samsung and other similar prosumer drives are not high end flash. Good enough for home gamers and most prosumers, absolutely! They would also likely yield significant improvements vs these levens in OP. I'm not trying to say those prosumer drives are bad drives. They aren't (The levens though, even new in box, absolutely are).

I'm merely saying that a small sample of some of the worst drives you can buy that are already beyond their stated wear and tear is frankly a poor sample to derive any real informed opinion on flash's potential or abilities. TL;DR: This really doesn't tell us much other than "bad flash is bad flash".