Regardless Of (No Matter)

8 related grammar points that express the same core idea - compared below so you can tell which one to reach for.

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～にかかわらず JLPT N2
～を問わず JLPT N2
Noun によらず JLPT N1
Noun のいかんにかかわらず JLPT N1
Noun のいかんによらず JLPT N1
Noun + はどうであれ JLPT N1
～だろうとなかろうと JLPT N1
どんなに～うが JLPT N1

Interchangeable forms

These are stylistic variants with no real difference in meaning or register - any one of them is correct, so there is no "which one" question to answer here.

Noun のいかんによらず　/　Noun によらず

にかかわらず / を問わず

Writing eligibility terms: an advert, a job posting, an application form.

～を問わず vs ～にかかわらず: Use を問わず: 経験を問わず, 年齢を問わず. It is the set phrase of official notices and takes a bare noun. にかかわらず is the everyday version and takes a wider range of forms, including clauses.