Can I use elements on a content entity layout canvas?
Yes. You can, although this is not a recommended approach and is discouraged.
You can use elements on content entity layout canvases, this is not recommend and is discouraged. As of version
5.6.0 elements are disabled by default from use on content entity layout canvases.
This can be set on a field by field basis within the layout canvas field settings.
It is recommended that components are developed and used on content entities. Please refer to our documentation on Creating a component layout.