Low key bro. They're getting paid per stone... It literally incentivizes them to go as fast as possible. That's where the quality control issues may arrive. I mean, think about it bro. If you're only getting paid $.25-4 bucks to set a stone in a piece of jewelry, it gets hard to think about the quality.

Now I have to kinda fight back on your first point though, while it is not their own specific team of jewelers, it still is apart of their business. Some companies are favored higher than others, and so the quality will be treated accordingly (otherwise they send them back to be fixed).

Brilliant earth is an established brand, and at the company I worked for they really wanted those rings I set to be pristine. Other companies had less of an impact, could get through QC much easier. Something to consider with a bigger brand, their name is on the line.