Do you want to work more than the 600 hours that you get from the government?
You can, but then you pay the normal social security contributions.
Once you have reached your quota of 600 hours, you owe normal social security contributions starting from the 601th hour worked.
Please note: even after reaching your 600 hours, you remain a student and you must therefore have a student agreement. The only difference lies in the amount of social contribution that you pay.
During the corona crisis extra measures have been taken regarding student work. Check all details on the page "Special measures when working in the care sector".