I work a lot in the UK. And NL and DE as well. I do not like talking about salaries, how much someone makes. But fresh out of uni I was above your senior numbers and besides being overly confident I did not do much more. My senior friends in the UK and NL and DE also make far more than you suggest. I think you are right that you need to be confident; without that you get abused. And I guess that is when labels like introvert get tossed around; if you do not ask or if you think you are not worth it...

Edit; Forgot to add the context; gross salaries per yet. In EU talking about net salaries make no sense at all so I assumed that.