@OP Are you in the Home Office, management at a store or club or hourly at the store or club. It makes somewhat of a difference.
If you are at the Home Office, you are salary and the expectation is to work 60 hours a week which includes holidays, vacations and weekends. (There are a handful of hourlies at the HO.) All leaders I knew had their laptops with them 24/7 and even worked on their vacations. Is there anyone else you can train to do your job in your absence so you can enjoy your time off?
If you are management in a store, unfortunately that is the life of retail. You are working closer to 80 hours a week for a pittance. Again, you need to surround yourself with leaders hat can make business decisions in your absence without having to call you.
If you are an hourlie at a store, they should not be calling you while off the clock. Don't pick up the phone. The job s—s far to much too put up with c-ap while not on the clock.
And you're right, the sad thing is if you aren't at the beck and call of Walmart, you're career will stall and you will be in a dead-end job not going anywhere. It's the retail way.
In my case, I compartmentalized my life and turned off Walmart as soon as I walked out the door. I wasn't paid enough to be available 24/7. I refused to answer the phone when I wasn't working. I made sure I had a life/work balance. And guess what? I was never promoted and stuck in the same position. I finally left for greener pastures.