Not examined in detail. Physical activity, management and local-source income need modelling.
Residence rights
Investor route requires evidence of business investment and at least EUR 50,000 in a Serbian bank account; other residence bases also exist.
Second citizenship
Residence permission does not confer citizenship. Any later nationality application is a separate process.
This is a brief route overview, not a complete tax or immigration assessment. Confirm current rules and your circumstances before committing funds or moving.