As an example, for 60,000 Euros (a more typical magnitude) your tax rate will be 26.55% if you are single, 16.73% if you are married (using splitting).
Money is fungible. You could equally say the crypto is taxed at a lower rate but then (a larger part) of your salary would be taxed at the higher bracket.
Income streams on the other hand are not nearly that fungible. You can either work full time or not at all most of the time.
So unless you can turn crypto trading into a full time (or more precisely minimum salary) gig, it is a marginal activity taxed at the marginal tax rate.
It is 42% if your income is higher than 57.918 Euro (2021). Most tech-related positions will achieve that.