How would you refer to a gender neutral subject with a reflexive pronoun?

It is unbelievable how a perpetrator will cast oneself in the role of victim.

That does not seem right. Is there a better word other than "oneself"? I thought "oneself" would refer to the narrator. Here I try to refer to the subject.

Themselves: It is possible to use a 'singular they' for pronouns, but to say "themselves" surely can not be correct as a gender neutral reflexive pronoun? According to this article, it would only seem to make sense when qualified by a singular they.

Themself: "The form is not widely accepted in standard English" according to the Oxford dictionary.

It is unbelievable how they, as a perpetrator, will cast themselves in the role of victim.

I'd like to avoid making the sentence this complex.