You can't generalize Soviet Russia this way, without quantifying the particular decade of the country's 74-year existence.
Prior to, and during the second world war, Russians worked like slaves, yes.
But starting in the 60s, the urban workweek became 41 hours over 6 days. [1] Kolhoz farmers, though, continued to work insane hours (for almost no pay) throughout the country's existence. (And much like in China, they could not leave the Kolhoz to go work in the cities.)
[1] Yes, some employers had really shitty overtime expectations. However, depending on other economic conditions, those employers could have also have a hard time attracting and retaining workers. Contrary to the popular belief in the West, you weren't just assigned a job at 16 that you had to work for the rest of your life.