Short answer
Soco only earns from the brand side. Creators always keep 100% of their commission.
How it works
Soco receives a small portion from the higher-commission links it negotiates with brands. This amount comes from the brand, not from the creator.
Your commission is never reduced or shared by Soco.
In short
Soco never lowers, reduces, or takes any percentage from the creator’s side. All of the commission earnings remain yours as a creator.