I believe in the First 100 days phenomenon but I vigorously ignore any bullshit about fixing major tickets within n days of starting at a company. First of all many places I’ve worked were deluding themselves about the feasibility of doing this. Their onboarding process inhibited any such wishes when I started there.

I’ve been doing user studies on developers for more than a dozen years. It got a lot easier once screen sharing was more common. But letting new hires or devs with brand new machines twist a little when going through the setup docs and taking notes. Or doing similar when I’ve made a major change or introduced a new API to see what fresh eyes see that I did not (or in some cases, that which was true but no longer is).

If at all possible I task them with fixing the docs. First, as you say, they don’t have the Curse of Knowledge, so how they word it will reach down the ladder behind them. Second, if what they say is completely wrong, then I can correct the miscommunication easier when they’ve used their own words to repeat back what we discussed.

Making edits to the wiki is usually the first contribution I want to see from a new hire. Even if it’s just untangling a run on sentence.