を問わず・にかかわらず・にもかかわらず: the difference
Regardless of, Whether or not, No matter, With or without
Tested 2 times in past papers
どんな役かは問わず、とにかく舞台に立ちたい。
I don't care what role it is — I just want to be on stage.
Regardless of, Whether or, No matter, With or without
Tested once in past papers
点数に関わらず、参加しただけで合格できる試験もある。
There are tests that you can pass just by attending, regardless of your score.
Despite, In spite of, Regardless, Nevertheless
Tested 2 times in past papers
勘違いしたにもかかわらず、彼は一切謝らない。
Even though he made a mistake, he will never apologize.
How to tell them apart
「を問わず」: 'no restriction' in rules and notices; follows a noun (年齢・性別) or a 〜か〜か / 〜かどうか / するしない pair.
「にかかわらず」: wider use; also follows a verb in positive and negative: 「参加するしないにかかわらず」.
「にもかかわらず」: completely different, 'despite': 「雨天にもかかわらず大勢の人が集まった」.