They start heavily corrupting data if left unpowered for around a year or two though, in case this gives anyone false confidence in a use case they aren't designed for.
No they don't. This myth originated when Alvin Cox (Seagate) gave a JEDEC presentation in 2015 talking about cell corruption when the drive reaches its end of life AND is stored at abnormal temperatures. Simply leaving flash unpowered won't corrupt data, especially consumer drives. This has been debunked by Alvin Cox and all the manufacturers of flash storage.
Its nonsense. For both SSD and HDD.
Although HDD do have a tendency to fail shorty after reuse if they where not used for years. This is due to lubrication decomposing afaik.
Just plugging them in often isn't enough to make them notice and refresh all data - the SSD doesn't have a clock in so doesn't know it's been unplugged for a long time.
The real answer is "for every month an SSD is powered down, leave it powered up for a day"
The original poster stated, "They start heavily corrupting data if left unpowered for around a year or two though, in case this gives anyone false confidence in a use case they aren't designed for." A person asked if all SSDs do that and you said, "Yes, all SSD's suffer this effect." This statement is wrong.
The AnandTech article even mentions the falsehoods and states it wants to clear up the confusion. A drive must meet certain conditions before data loss begins. Simply putting a backup or thumb drive in a safe for several years isn't going to cause data loss and the AnandTech article comes to this conclusion.
Here is another article from PCWorld with commentary from the authors of the 2015 JEDEC presentation that started this hysteria.
That's 2015, densities have gotten much higher since then. I'll take back heavily corrupting, I've seen it happen but I don't know that it is the norm within 1-2 years.