Impossible. DNA degrades very quickly. Half-life is ~520 years, and you'd assume any "storage" done quickly and ad-hoc (as these things always are) would not be ideal conditions to maximize this number.
> That's the typical half life. The record is ~2 million years, obviously just tiny fragments
Half-life of DNA is the time it takes for half the bonds to snap. Far longer than 2 million years is achievable based on that half-life, at least under ideal conditions.
https://www.pbs.org/newshour/science/unlocking-the-oldest-kn...