If you have anything of real value on that QLC drive, I would definitely keep a backup on an external hard drive, or maybe even BD-R M-Discs. SSDs, especially QLC drives, are not good for long term archival. Here's why:
QLC drives use 16 distinct charge levels in their flash cells to store 4 bits of data (2^4 =16). For reference, TLC drives use 8 distinct charge levels, MLC drives use 4 charge levels, and SLC drives use just 2 charge levels. Because of physics, electrons will gradually leak out of those flash cells over time (a period of years). At some point, enough electrons will have been lost that those 16 charge levels in a cell cannot be maintained, and the data becomes corrupt. This bit rot will obvously happen faster with a QLC drive than other types of SSDs that pack fewer bits into a flash cell.
SLC cells can last a very long time, particularly at low density. There's a lot of PS1 memory cards out there with perfectly readable data on them, for example.
You shouldn't generally trust an SSD to hold data longer than a year if it's disconnected from power. The cells get rewritten occasionally when the drive has power, so it'll last probably for at least a decade, but remove power and the data starts to decay.
The hotter the flash cells were when written, the longer the data will last (so you
want the flash cells running hot), but the hotter the drive is when unpowered, the faster the charge dissipates. At least as of a few years ago, a drive that wrote data at room temperature, and was then stored at room temperature, would generally retain it for about two years, but I think that stat may have been for TLC drives. QLC drives may not last that long.
If the drive is hot enough in storage (I think circa 50C, so that wouldn't normally happen except in direct sunlight), you can lose data within a couple of weeks.
