I think it's probably fairly random. I.e. you're just as likely to have a "do nothing" job in a FAANG as in some other random corps. But I don't think you can start doing nothing right after being hired - usually people are hired because there's more work in a team that the existing headcount can handle. So, you have to work for some time and then count on "falling into the cracks" - landing in a place where there's less work than people capable of doing it.

BTW I recommend against startups (pre big funding). In startups, the owners watch costs like hawks and there's zero chance of slacking off.

BTW2: if you're good with people, I recommend a Scrum master role. From my observations over the years, these folks have almost zero workload and absolutely zero responsibility for anything. It's slacker's paradise - you just have to be comfortable with babbling on meetings/calls for the majority of the day.