grammatical case - Whom should I say is calling?

Note, originally my question was "should I ask" instead of what I meant, which is "should I say". Sorry for the confusion.

If I do an internet search about:

Whom should/shall I say is calling.

I invariably get blogs and articles saying that this is incorrect, and probably a form of hypercorrection.

This question follows from a previous question based on an Oxford Living Dictionaries article about whom and who.

In the article it claims that in both:

• ✗ He is demanding £5,000 from the elderly woman whom has ruined his life.
  and
  


• ✗ Mr Reynolds is highly critical of journalists, whom just use labels to describe him.

the use of whom is wrong, and it should be who. This seems to be agreed to by the users that contributed to the previous question I linked.

However the Oxford Living Dictionaries also claims that the following two are incorrect:

• ✗ He is demanding £5,000 from the elderly woman whom he claims has ruined his life.




• ✗ Mr Reynolds is highly critical of journalists, whom he says just use labels to describe him.

However on these two examples the majority seemed to say that objection to using whom in the last two is an old prescriptivist objection, and to quote an answerer:

According to many respected grammarians, the article is incorrect ...

So:

• He is the person whom won the race.(Wrong)
  


• He is the person whom I say won the race.(Acceptable?)
  

In the second example whom appears to be both subject and object, however more particularly "whom" is the subject of "won the race", but the object of the whole clause seems "I say won the race". At least that's what I understood from the point.

If this is acceptable, then in the case of "Whom should I say is calling?" Doesn't the following apply:

• Whom is calling?(Wrong)
  


• Whom should I say is calling?(Acceptable?)
  

If we turn these questions into statements I think we get:

• He is calling.
  


• He is the person whom I should say is calling.
  or
  


• He is whom I should say is calling.
  

Is this analagous to the other cases, and therefore saying "Whom should I say is calling?" is not incorrect?

I'm not sure what the answer is, but every every single result I saw about "Whom should/shall I say is calling?" have all said that it's incorrect and that it should be "Who", mainly because the "Who" is doing the calling and therefore the subject.

Who/whom shall I say is calling?

He is calling.

Who shall I say is calling?
englishessaywritingtips.com

Correct: Whom did you speak to earlier?
Correct: A man, whom I
have never seen before, was asking about you.
Incorrect: Whom
should I say is calling?
grammarly.com

On this usingenglish.com forum thread an English teacher calls it an instance of hypercorrection.
usingenglish.com

On this Quora question all the top answers say it should be "who".

In this sentence, "he" is the correct choice, so you would choose "who" for the question.
Quora question

I take it given all this information my instinct is wrong about this?