I have been looking at this for some time. Everywhere you look you get different opinions on the Golden Visa. It seems it is only useful as a route to get a TIE and eventually full residency. It was discussed on the recent Zoom meeting on Facebook with the Tenerife UK Consul and several experts. The outcome was not encouraging.
Other countries, for example Portugal, Finland and Cyprus have schemes where you can buy into unlimited "Golden" visas, but there is pressure on them to stop. So, if Spain were to allow it now, or in future, they may withdraw. I had thought of topping up my property value with a cheap rental property to reach the 500 k euros and asked about it at Paul Ruane's office. They did not seem interested, which is odd because there was a potential sale for them.
I will take a further look through my notes tomorrow and possibly follow up with Paul Ruane when we next visit, hopefully in May.