The food stays good until Spoilage_days has been reached, then daily there’s a “die roll” to see if it’ll stay fresh or go stale. So with some luck the spoilage is closer to ~18 days to stale, then another 2-3 days to actually spoiling. Store it in cellar and in winter, below freezing, gets no spoilage checks. Even in summer the spoilage checks in cellar are either delayed, or get pretty decent bonus to keep fresh.
Problem with hot smoking is that the protein has too much moisture left in it. Exterior cooks, inside stays at pretty much full moisture content. That’s why it’s so darn tasty!
For what it’s worth, it takes 36-48 hours, IRL, to salt&vinegar cure, then with mechanical airflow, 6-7 days to remove 50-60% of water weight. That gives you meat that stays shelf stable for ~8 months.
I have never had hot smoked salmon last longer than 2 days: it gets eaten up!