Refactor similar methods but with different return types [closed]

I have two methods:

public ActionResult<IEnumerable<IDataObject>> GetRelatedObjects([CanBeNull] string className, [CanBeNull] string primaryKey, [CanBeNull] string relationName){  if (string.IsNullOrWhiteSpace(primaryKey))  {    return BadRequest("Primary key cannot be empty.");  }  if (!TryGetClass(className, out var metaClass))  {    return NotFound($"Class [{className}] does not exist.");  }  if (!metaClass.Properties.TryGetValue(relationName, out var property))  {    return NotFound($"Class [{metaClass}] does not contain property [{relationName}].");  }  if (!(property is IMetaRelation relation))  {    return BadRequest($"Property [{relationName}] is not a relation.");  }  if (relation.Target.Cardinality != MetaCardinality.Multiple)  {    return BadRequest(`$"Relation [{relationName}] has multiple cardinality."`);  }  if (!_primaryKeyHandler.TryParsePrimaryKey(metaClass, primaryKey, out var primaryKeyValues))  {    return BadRequest("Cannot convert the primaryKey to the correct type.");  }  if (!_dataCalculator.SupportsData(metaClass))  {    return BadRequest($"The class [{className}] is not persisted");  }  var metaObject = _dataAccess.GetObject<IDataObject>(DataSession, metaClass, primaryKeyValues);  if (metaObject == null)  {    return NotFound($"The metaObject for the primaryKey [{primaryKey}] nad the class [{className}] cannot be empty.");  }  // The validations above are the same as for GetRelatedObject()  try  {    var list = _dataAccess.GetRelatedList<IDataObject>(DataSession, metaClass, primaryKeyValues, relation);    return new ActionResult<IEnumerable<IDataObject>>(list);  }  catch (InvalidAuthorizationException)  {    return Unauthorized();  }}

and the second:

public ActionResult<IDataObject> GetRelatedObject([CanBeNull] string className, [CanBeNull] string primaryKey, [CanBeNull] string relationName){  if (string.IsNullOrWhiteSpace(primaryKey))  {    return BadRequest("Primary key cannot be empty.");  }  if (!TryGetClass(className, out var metaClass))  {    return NotFound($"Class [{className}] does not exist.");  }  if (!metaClass.Properties.TryGetValue(relationName, out var property))  {    return NotFound($"Class [{metaClass}] does not contain property [{relationName}].");  }  if (!(property is IMetaRelation relation))  {    return BadRequest($"Property [{relationName}] is not a relation.");  }  if (relation.Target.Cardinality == MetaCardinality.Multiple)  {    return BadRequest($"Relation [{relationName}] has multiple cardinality.");  }  if (!_primaryKeyHandler.TryParsePrimaryKey(metaClass, primaryKey, out var primaryKeyValues))  {    return BadRequest("Cannot convert the primaryKey to the correct type.");  }  if (!_dataCalculator.SupportsData(metaClass))  {    return BadRequest($"The class [{className}] is not persisted");  }  var metaObject = _dataAccess.GetObject<IDataObject>(DataSession, metaClass, primaryKeyValues);  if (metaObject == null)  {    return NotFound($"The metaObject for the primaryKey [{primaryKey}] nad the class [{className}] cannot be empty.");  }  // The validations above are the same as for GetRelatedObjects()  try  {    var relationValue = metaObject.GetObject<IDataObject>(relation);    return new ActionResult<IDataObject>(relationValue);  }  catch (InvalidAuthorizationException)  {    return Unauthorized();  }}

As marked with the comment in the code, the validations are the same in both methods. In both methods there is a small part of code which isn't the same.Also the return type is different in both methods.

I am trying to refactor the validations inside the methods into one seperate method.

Here is my attempt:

private void RelatedObject(string className, string primaryKey, string relationName, out IMetaRelation metaRelation, out IDataObject metaObject, out ActionResult<IDataObject> actionResult, out IDictionary<IMetaProperty, object> primaryKeyValues, out IMetaClass metaClass)    {      actionResult = null;      metaRelation = null;      if (string.IsNullOrWhiteSpace(primaryKey))      {        actionResult = BadRequest("Primary key cannot be empty.");      }      if (!TryGetClass(className, out metaClass))      {        actionResult = NotFound($"Class [{className}] does not exist.");      }      if (!metaClass.Properties.TryGetValue(relationName, out var property))      {        actionResult = NotFound($"Class [{metaClass}] does not contain property [{relationName}].");      }      if (!(property is IMetaRelation relation))      {        actionResult = BadRequest($"Property [{relationName}] is not a relation.");      }      if (relation.Target.Cardinality == MetaCardinality.Multiple)      {        actionResult = BadRequest($"Relation [{relationName}] has multiple cardinality.");      }      if (!_primaryKeyHandler.TryParsePrimaryKey(metaClass, primaryKey, out primaryKeyValues))      {        actionResult = BadRequest("Cannot convert the primaryKey to the correct type.");      }      if (!_dataCalculator.SupportsData(metaClass))      {        actionResult = BadRequest($"The class [{className}] is not persisted");      }      metaObject = _dataAccess.GetObject<IDataObject>(DataSession, metaClass, primaryKeyValues);      if (metaObject == null)      {        actionResult = NotFound($"The metaObject for the primaryKey [{primaryKey}] nad the class [{className}] cannot be empty.");      }    }

And here is the call inside GetRelatedObject:

public ActionResult<IDataObject> GetRelatedObject([CanBeNull] string className, [CanBeNull] string primaryKey, [CanBeNull] string relationName){  RelatedObject(className, primaryKey, relationName, out var relation, out var metaObject, out var actionResult, out var primaryKeyValues, out var metaClass);  if (actionResult != null)  {    return actionResult;  }  try  {    var relationValue = metaObject.GetObject<IDataObject>(relation);    return new ActionResult<IDataObject>(relationValue);  }  catch (InvalidAuthorizationException)  {    return Unauthorized();  }}

And here is the call inside GetRelatedObjects:

public ActionResult<IEnumerable<IDataObject>> GetRelatedObjects([CanBeNull] string className, [CanBeNull] string primaryKey, [CanBeNull] string relationName)    {      RelatedObject(className, primaryKey, relationName, out var relation, out var metaObject, out var actionResult, out var primaryKeyValues, out var metaClass);      if (actionResult != null)      {        return actionResult;      }      try      {        var list = _dataAccess.GetRelatedList<IDataObject>(DataSession, metaClass, primaryKeyValues, relation);        return new ActionResult<IEnumerable<IDataObject>>(list);      }      catch (InvalidAuthorizationException)      {        return Unauthorized();      }    }

There are multiple problems with my attempt:

1. GetRelatedObjects and GetRelatedObject have different return types and my refactored method can only support one
2. Some of the out variables are not used GetRelatedObject but are used GetRelatedObjects and reversed

What would be the needed changes to improve my solution so I can get rid of my problems?