It's really easy to see hours as the only real problem. But they really aren't. Another article I read talked about how people who are constantly ruminating about work but work about 40 hours are at a higher risk for health impacts than those working many more.
I know this personally; I'm currently on a leave of absence because I burned out. And no amount of 'boundaries' around work kept it out of my thoughts all the time.
It really was about the other factors in the six factor model. Values drifting. Loss of control. Worsening relationship with my lead and no real peers to work with.
It would have been very different, even with more work, if I felt like I was part of a team trying to solve problems, rather than trying to put out the latest needless fire my boss created.