SysML v2 textual import should probably be doable on the root of the tree (the .sysml resource) such that a user with a complete SysML v2 model (with multiple packages as roots of the textual file) ...

Currently, org.eclipse.syson.application.services.SysMLv2EditService.createRootObject(IEditingContext, UUID, String, String) does not account for non-SysML model elements: For a non-EMF editing ...