Do I need approval before I can even apply for the Romanian business visa?

This is not a visa you apply for cold. The business/investor route requires prior endorsement of your project, including a technical opinion on your business plan from the Romanian Agency for Investments and Foreign Trade and approval connected to the relevant Ministry for small and medium enterprises.

Only once that endorsement is in place do you lodge the long-stay visa application with the consulate, alongside documents such as a criminal record certificate, travel medical insurance, and proof of accommodation.

Because the business-plan approval is the gatekeeper, the quality and credibility of your plan is the single most important part of the application.