I've had people try the env issue thing. I asked them to never try longer than 15 minutes to solve an env issue by themselves. Post on the public dev channel for help or ask me privately if they don't feel comfortable with it (it happens, that's OK). A lot of people just aren't good at troubleshooting env issues and I happen to be good at it even if I have never had that issue and I keep an eye on others posting and often can find a solution for people quickly. It's amazing how many people can't read error output, especially stack traces, and figure out which is the relevant message to search by.
Broken CI same thing really. And it's easy to compare if it's just them or everyone's builds are broken.
Complexity I offer help. Pairing for as long as needed. I've had a few guys where it became clear here that they really just weren't good. There are many signs here that you can collect and document. I've also done Re-implementations from scratch (not looking at their code) in some instances, proving their "hidden complexity" that took a week to not solve took me literally an hour to code down.