As a visa programme, this scheme is not equivalent to getting a Spanish passport. The Spanish Golden Visa grants residency through investment, not citizenship, which is required to obtain a passport and gain the full rights of a Spanish/EU citizen.
If you (and any family members) continue to uphold the requirements of the visa, you can upgrade to permanent residency after 5 years. Then, as a permanent resident, you can apply to become a Spanish citizen after 10 years of Spanish residency.
To become a naturalised Spanish citizen, you must meet particular criteria – including demonstrating strong ties to the country, reasonable fluency in the language, financial stability, and the absence of a criminal record, in addition to living in Spain for at least half of each year for these years to qualify.
While this visa can provide a route to legal citizenship, it is not a ‘Golden Passport’ – but it does provide a ‘fast track’ for citizens of countries that were formerly Spanish colonies. Nationals from these countries can apply for citizenship and then a Spanish passport after only 2 years of residency with a Golden Visa.