Depends on the type of job. I suspect that creative work (not art, but also things like software development) have a threshold after which more work brings diminishing returns while simultaneously worsening future output. No idea what that threshold is. Also, manual labor unfortunately doesn't seem to share this property to the same degree.
I don't know why exactly, but I don't get almost any "watch part 2" content on YouTube shorts. That's actually the only reason I started using it instead of TikTok - those really enraged me.
> Due to its history the United States can be described as an immigration country.
Being a nation of immigrants does not mean the majority of the population are migrants at any given point in time. You need to consider how many waves of migration have arrived in the USA one after another, not all at once.