A lot of d&discourse seems to come from DMs who are put-upon that their hours/weeks/months of prep time is ruined by players [doing something in or outside the game] and my response to them is... perhaps you should not spend that much time preparing

Not only do you not need to but you shouldn’t.

Like a lot of the replies to this thread are about how DMs aren’t appreciated for all the work they do and it’s offensive to be on your phone, and look there’s all sorts of social dynamics around what it looks like to pay attention to something