Is the ÖSD Zertifikat C2 / Wirtschaftssprache Deutsch equivalent to an economic education?

No, ÖSD Zertifikat C2 / Wirtschaftssprache Deutsch is merely proof of language competence to the level C2. The „Wirtschaftssprache Deutsch“ exam assesses the professional and economic language competence necessary for business-related professions. Please note, economic knowhow is not subject matter of the exam.