I can echo that sentiment. Employers will try to take advantage of you. Don't let them. A consequence of cellular phones becoming mainstays in culture is that even the most menial jobs are practically always on call. If you're old enough to remember the 90s, pagers were a thing for business men and healthcare workers and few other vocations. Your employers might have your landline number for emergencies, but it could be tied up by dial-up or other phone calls, so they couldn't always get through.

Basically their access to you was fettered and consciously limited to your working hours.

Nowadays with cell phones as a main stay and the internet being prolific for all forms of communication, your employers expect you to basically be on call 24/7. Most aren't so unreasonable, but they design schedules around not letting you take vacation and with the expectation that you will come in on a moment's notice to fill in for anyone who calls out. If they can't reach you, they get angry as if it were a breach of contract.

I remember in 2020 when my own employers filled out paper work and passed out papers to mark us as essential workers (after Zero Houring every hourly they possibly could). What I do is nowhere near essential, but god forbid profits take a backseat to anything. They tried to get me to take on duties for positions that I was not trained for without training me on them. "Rise to the occasion! Be thankful you still have your job!" - "Is my pay going to rise with the extra work?" - "We can't afford that right now!" - "Oh. Ok. Will you train me on the extra duties?" - "No, just learn by doing it!"

So I did the extra work without knowing how to do it, got lambasted for doing it poorly, but they soon stopped expecting me to do it at all because it just had to be redone anyway.