In USA/Canada boss just going to call you during your vacations, because it's an emergency. So those task won't be understood and will continue to be seen as an exception.
Maybe time to look for a new employer.
I am a third year junior associate at a law firm, it would interest me how you transitioned.
Even at Amazon, when I left work I left behind all ways to communicate and my bosses respected that. Nearly a decade there and never did a boss try to reach me on vacation.
(I've also seen a person who believed he was indispensable and thought because of that he could behave like an asshole. Very satisfying to see him get fired.)