the correct answer is that they do not.
you can check stats and specs on dacs. while you may find the odd one that is particularly terrible, mostly in very low end equipment from 40 years ago, the reality is that the specs on dacs have been standardized for decades. the companies don't save money by trying to sell you dacs with low specs, but they may make money by trying to upsell you dacs with specific brand names, or trivial differences.
the reality is that the cheapest dacs on the market in 2026 sound as good as the highest end ones do. there's no difference. it's just marketing, it's not science.