4 day week is simply a PR effort. I have been following the company on LinkedIn and even the current CEO put out "words of wisdom" and he likes them himself.. weird
There is some truth to this, not the job for everyone. I personally know the current CEO and I was surprised when he joined the company as CTO. As far as I know CTO at the very least should be familiar with latest and greatest technology.
If have a nursing degree it's easy to immigrate to USA, in fact you will be coming in with a green card unlike tech worker. So to your point, US does prioritize nurses over others. Doctors are different and it's incredibly difficult for a doctor with a foreign degree to practice in US. I know this for a fact since I come a place where almost every other house has a nurse working in Europe/US
I recently got this question for an engineering manager position. I got it done in an hour and 20 minute with all test cases presented passing. But I don't particularly think this is a good question for senior level candidates since implementing is mostly copy pasting existing functions and renaming them and adding a new memcached VERB.