RE: Not able to enable the subgrid for the Read only user
It seems by design because the method setDisabled=false is not design to work if the user doesn’t have the privilege to update that record, which is expected because if the record is ‘read only’ for that user, is not expected that the user has the privilege to manipulate access into the field in the UI.
To confirm this behavior you can test with an User containing only READ privilege against this Entity record, try to run setDisabled= false against a simple text Field, for example.
Result: It will not work, the field will continue inaccessible/"read only" in the UI;
Performing same test with an User containing a Security Role with full privileges against this Entity record, when we run setDisabled= false against a simple text Field, it will work, and the field will become accessible in the UI;
You will verify the same behavior for the Grid View360PCFExplorer, when you test it with an User containing only READ privilege against this Entity record, setDisabled=false will not work there either, as expected. Hence View360PCFExplorer will remains as ‘read only’ in the UI, not allowing the User to click/access the control, exactly as can be verified in a simple text field.