Only one large brand that I have seen which is fairly consistent and easily accessible to most is Thorne.

Most companies are buying from larger distributors, and it is those companies and distributors that are a problem since they don't do proper QC. Factories in China and India, where the vast majority of supplements are manufactured, don't care, and they are happy to lie or use dry labs to fake their results. I'll sometimes spend 6 months in testing before we actually get a lot that meets spec, and that includes a lot of arguing with suppliers, which is tiring.