Is it possible to declare custom content and have it not show up in the app sidebar or be disabled by default?
https://developer.atlassian.com/cloud/confluence/modules/custom-content/
Custom Content UI Support seems to be a required property and when declared it appears to show up on the sidebar.
Here is a similar question but not answered:
The real problem is we want to define more than more custom items but not have them all displayed on the sidebar.