We have far more leisure time than our parents did, and way more than our grandparents. Our kids will have far more leisure time than us.
It's hard to compare in part because there are very different lifestyles. As a member of the fortunate "programmer class" I have high pay, health insurance, easy job portability. This leads to pretty reasonable vacation schedules, good lifespan. Overwork expectations and stress are the downsides, but these are within my control somewhat and I can just get another job.
This research paper says leisure time increased noticeably from 1965 to 2003 - an increase of 6-8 hours per week for men and 4-8 for women. https://www.nber.org/papers/w12082. This is a surprise to me and goes against my intuition. Maybe we always feel like we are getting a bad deal.
Don't forget the sizable number of lower hourly wage Americans where some people work many hours at low pay and barely support themselves. Americans seem to work significantly more than our European peers https://20somethingfinance.com/american-hours-worked-product....
I dunno. When my parents got home from work, they were done with work except for rare exceptions.
Now a lot of people have to deal with working with technology that is supposed to have 100% uptime but of course that never happens so random freakout fix something. And even if you don't work directly in tech, everyone wants to be able to get ahold of you because nothing can possibly wait. We deal with things around the world timezones way more than in the past so that just increases the chance that someone needs to get ahold of you because something in another country where it's the work hours need something.
So I'm not really sure about your theory that we have more leisure time.. maybe(?) we have a little more time, but it's certainly not true disconnecting. I can't go on vacation without having to worry I will have to work or check in on things. Even it's only a little bit, it's still there.
Having leisure time isn't new to our generation (any of them).