Fining within the EU is not a solved problem. In 2019, millions of international fines went uncollected because the infrastructure still was buggy. So, legally

Fining within the EU is not a solved problem. In 2019, millions of international fines went uncollected because the infrastructure still was buggy. So, legally it is a solved problem, but practical enforcement is not (yet). Border control does not (currently) detect fines and prevent people from leaving to non-EU locations.