But why did you left if you had a great QoL?

Because I was able to get a better QoL elsewhere in the EU.

The average worker in The Netherlands has one of the best QoL compared to average workers in other countries. But the Dutch income leveling and benefit system makes it so a high earner doesn’t have a significantly better QoL. Someone earning €30k has roughly the same spending power as someone earning €50k. (edit: net income after tax and benefits is €42k versus €47k for those two incomes but the person earning €30k has access to cheaper government housing)

In other countries, earning more gives you a better QoL.