There is a Graph API to publish your app to the organization app catalog. https://learn.microsoft.com/en-us/graph/api/teamsapp-publish?tabs=http&view=graph-rest-1.0#example-2-upload-a-new-application-for-review-to-an-organizations-app-catalog&preserve-view=true

I am using this API in my PowerShell module to publish the declarative agent automatically.

https://github.com/code365opensource/microsoft.copilot.toolkit/