Sitecore XM Cloud is a SaaS application, so 3rd party integrations need to be approached very differently. While currently it is technically possibly to deploy customizations to the platform (CM), this is actively discouraged and is only available for scenarios where there are no other options. Deploying customizations can put you at risk for future updates, especially if there are breaking changes. Because of this, deploying Nuget packages would not be the right way to create a connector.
Sitecore Connect
When connecting XM Cloud to 3rd party applications, one option is Sitecore Connect (a white label of Workato. This is a low code system that allows you to configure recipes that pull data from one system, do something with it and push it to another and many other things. This could be an option when integrating with an existing application that has an API available
API First
If you want to provide some new functionality to XM Cloud, for example, language translation, you would need to build your application that does the work outside of XM Cloud. This could be created as another SaaS application or a codebase that a client can host themselves.
Your application can integrate with XM Cloud via webhooks and the Authoring and Management GraphQL API.
In the above example, you might use the Workflow webhooks to create a workflow command that submits some content to your application for translation. Once the content has been translated, then your application can write that data back to XM Cloud using the Authoring GraphQL API.
These are the patterns that should be followed when creating a connector or 3rd party functionality for XM Cloud.
