Here in the UK you get 26 days leave a year roughly so it's not impossible to take a week off. I hear the US makes this much more difficult. It would have to be paid obviously.
I wonder if "audition time" could be a sort of industry standard? FAANG announced they expect/allow it and will only do business with others who do too.
Ultimately it would be better to know someone might leave soon and to get to actually know what they do while you can still ask them before they just leave and your stuck without them. But I doubt managers would welcome it.
I'm no good at it. So I'm stuck in most places. The last big Corp I worked at gave me all the projects from a guy called dave. He was lazy and useless but he went to school with the bosses boss. So he was being promoted and moved to the states.
In tech he'd have been sacked or sidelined. But on the business side he was allowed to wade in, break things (piss off clients I spent months calming down for instance) and then wonder off and act like it was all my problem. Which it was.
There was little chance if get promoted (I don't play golf and there were plenty of people who went to school with management waiting for a nice job).
Partly it was my mistake: I am not very charismatic. But they kept saying they wanted someone who'd tell it like it is and deliver projects and get clients off their backs.