Hiltz competes in women's races, and (as far as I know) is not physically transitioning to male via hormones or surgery. I can only conclude they are a biological woman, competing as a woman. I see no conflict between this, and indentifying as non-binary, and using they/them pronouns.
The best way to find out facts about transgender or non-binary people, is to ask them. Each person has the right to identify as they see fit. Furthermore, it's important to understand that these identifications arise from the heart, mind and personal feelings of each person.
The idea that there exists recruitment or "grooming" of trans, non-binary or LGBTQ people is false. This idea is promoted by cynical politicians and media people who have an agenda to divide people, and divert attention from issues of substance, for personal or political gain. These ideas are also taken up by sincere people who lack critical thinking skills, who have been manipulated by said cynical politicians and media talking heads.
Anyhow, great run Nikki and good luck at Worlds.