Solution:
Exporting the provider config is impossible via Config-Sync as this config requires env variables.
Instead I configured them in Strapi Bootstrap at ./src/index.ts.
I used the Strapi core store to set the config via strapi.store({ key: 'grant', ...other stuff }).set(new data here) method. I don’t remember off the top of my head the other two properties to be passed to the store but I can post the rest tomorrow 