The issuance of an investor resident visa shall be legally sufficient to reside and work in Spain during its validity. You do not need to apply for a separate work permit. Also, you do not have to find an employer to sponsor you, as once you get the investor visa you are allowed to reside and work in Spain during the validity of the visa.
How can I apply for a work permit as a real estate buyer of Spain?
I learned that if I invest 500,000 euros in the real estate market of Spain, I will be able to get a resident permit. After obtaining the permit, I want to look for a job or establish my own business in Madrid or Barcelona. Do I need to apply for a separate work permit? Do I need to find an employer who wants to sponsor me?