No, if A's PRs always bounce because the testers find bugs then A is going to look like an idiot. Then again you need to work at a place that actually employs testers.

If B always submits PRs and they always go straight to merged in prod, then B knows what he's doing

I've seen a lot of fairly explicit discussions around "this timeline will require cutting these corners and cost this much time to fix later or else it will cause these problems", and also some relatively internal discussions around "how strongly can we rely on promises that the project won't get dropped before all the cleanup is done, and how does that impact what options we can present".

Most bugs are trivial to identify and trivial to fix. At least that’s been my experience from 15 years as a SWE in start ups and FANG alike.

Yes, I’ve worked on bugs that have taken weeks to fully resolve. But those are rare.