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Então seria NO MATTER sempre antes de um WHAT
DOESN'T MATTER com algum sujeito na terceira pessoa do singular
No matter and it doesn’t matter
It doesn’t matter does not mean the same as no matter. It is used to introduce a sentence that has only one clause.
It doesn’t matter what she does. (NOT No matter what she does.)
It doesn’t matter how he reacts.
Note that matter is one of those verbs that are not used in continuous forms.
Her objections don’t matter. (NOT Her objections aren’t mattering.)