What is the rationale for a government trying to block one of its citizens for becoming EU prosecutor?

Question

Romania’s former head of the anti-corruption directorate DNA has significant chances of becoming European Prosecutor's Office.

According to Wikipedia, an EU Prosecutor can investigate fraud across EU, but there are some limitations:

The EPPO may request a suspect's arrest, but this must be confirmed by the relevant national authority.

This article argues about Romanian government moving to block Kovesi to become EU prosecutor:

Prosecutors applying for the post of European chief prosecutor must be treated fairly, the European Commission said Thursday, after Romania moved to block one of its own nationals.

The same article emphasizes government's efforts to undermine the judiciary:

Romania's ruling Social Democracy Party embarked on a contentious judicial overhaul two years ago, sparking protests. Critics, including the EU and the U.S., claimed the changes would undermine the independence of the judiciary and efforts to combat high-level corruption.

Since one cannot be arrested unless a national prosecutor asks for it, I am wondering why make such a tremendous effort to stop a person becoming an EU prosecutor.

Question: What is the rationale for a government trying to block one of its citizens for becoming EU prosecutor?

Answer 1

Retribution

The rationale of the Romanian government in this case is that the individual in question, in her role as head of the Romanian Anti-Corruption agency, has launched investigations on more or less the whole political establishment of Romania.

Becoming a major EU prosector would, most probably, give her more investigative power. And that's something you do not want, if you're on the receiving end of the anti-corruption investigations.

See relevant articles in the media, e.g. 1, 2