mijnzelf
Mijnzelf is a term that is not part of standard Dutch usage. It is formed from the possessive determiner mijn (my) and the reflexive pronoun zelf (self), and is sometimes encountered in informal writing or as a misspelling. However, in modern Dutch the correct reflexive forms are me, mezelf, mijzelf, uzelf, onszelf, or jezelf, depending on person and formality.
In practice, mezelf is the common emphatic reflexive form for the first person singular, used to refer
Usage considerations: if you want to express “myself” in standard Dutch, prefer mezelf or mijzelf as appropriate
See also: Zelf, Mezelf, Mijzelf, Zelfconcept, Dutch reflexive pronouns.