"Devops people know" means that the key must be some secret property. Or you need to use the key during the deployment artifact building pipeline, and then deploy the artifacts with clear-text secrets.
> vs storing hundreds of secrets.
Then serialize them to JSON or whatever.
> also it allows adding new secrets without knowing decryption key - I think it is important for collaboration
So basically, you want developers (who don't have access to prod) to add random properties that your peers can't see during the code review? Ok...
Sorry, there's just no way the encrypted secrets in git are a good idea for general-purpose software.