tl;dr: I don’t know. But YOU should achieve it!
Some swear on only working a few hours each day, but have maximum focus and productivity in that time. Others would never work on weekends, to get time off for friends, family, sports and leisure. On the other hand, there are many successful people who are working 90 hours a week. There is a famous quote that Bill Gates never took a day off until he was 31.
Personally, I don’t think there is a universal concept or rule to achieve the perfect balance between work and life. For some, work is also part of living, while others work to earn money to live. If you want to find a balance, the first step is to actually be open to change your behavior and find a way to measure your change and success. Otherwise, you don’t really know if you improved your life. This can be as simple as reflecting about your goals, habits, and so on once a day/week.
What research has found and many productive people suggest is to regularly find time for yourself (to think without pressure, do what you love to do), find a way to exercise (do sports, meditate!), take time off (e.g. a daily 15-minute walk, a weekend without emails, a real vacation), work a job you love, plan and stick to a daily routine, and to minimize the time you spend on things you have (and don’t want) to do.
Some blog posts I’ve found interesting wrt. to work-life-balance:
I wish you a lot of fun with trying out new things and good luck with finding YOUR own way!