The NOR flash memory datasheet says: TA Ambient Operating Temperature –40 to 85 °C TSTG Storage Temperature –65 to 150 °C
Which of these two ranges is the long-term storage range without using the chip to retain all recorded data for 20 years? I am confused because the manufacturer mentions data retention for 20 years but does not say which range is responsible for the storage of the chip soldered on the PCB.
Data retention time is subject to Temperature.
Here is an example in this datasheet
In the case where the application ceases to be in use for a while, the device will still be able to retain the data for 20 years at roughly 35°C or two years at a constant storage temperature of 55°C.
I am confused because the manufacturer mentions data retention for 20 years but does not say which range is responsible for the storage of the chip soldered on the PCB.
Ask the manufacturer. If you can't get an answer, you'll need to use a more expensive part from a manufacturer that actually supports their customers.
Guarantees as to the data retention cost real R&D and will cost you money. You won't get it for cheap in consumer products. And even if you did, what can you do if you lose your data? Most manufacturers limit the warranty claims to the price you paid. So, worst case, if you lose the data prematurely, and file a warranty claim, the manufacturer may refund the money you paid for the drive and tell you to go away. The data may be worth much more than that. That's what backups are for, that's what disk scrubbing is for, that's what business continuity insurance is for.
If you configure the drive as a part of a RAID array, even just a single-disk RAID 0, any decent RAID controller (even if just software-based) will offer so-called Scrub Read. The controller reads the entire space allocated to the volume in the background, letting the drive (whether HDD or SSD or NVMe) detect marginal reads and rewrite or relocate the data.
You can also lose data because of a failure of the SSD as a whole rather than due to data retention issues. So you still need backups, because things fail randomly. Say your drive/computer may be powered from mains and a lightning strike overvoltage may destroy/damage them. Or a data center or your hotel or home may get flooded. Nothing to do with the SSD, just bad luck. Do your backups.
If you need those data retention guarantees for an industrial use or use in a product, you'll need to deal with vendors that support OEMs, and the prices you pay will be significantly higher. That's to be expected.
