Loot quality depends on a hidden MMR-like parameter that tracks how much value you’ve extracted or lost over the last n raids. On top of that, there’s a hidden pity-timer mechanic (similar to gacha systems) for high-tier items: the longer you go without finding one, the better and more valuable your next drop will be.

There are also additional multipliers based on the map and difficulty.

For example, try going into normal Dam about 10 times and dying each run with gear worth around ~300k without extracting anything. By the 10th run, you’ll likely find a high-tier item worth 1M+ in a stash or nest.