You are technically correct but seem to be applying common law standards to civil law countries.

Unlike common law judiciary, civil law judiciary in and of itself has investigatory powers and judges don’t just hear arguments but can order their own investigations and are significantly more independent than in common law.

This can cut both ways, yes in theory the judge can accept evidence the prosecution obtained illegally, but the judges can also call the prosecutions bluff and call their own witnesses or order an independent expert to provide their own opinion, even if defense is unable to.