I don't think it's that she's burned out or doesn't enjoy skating, rather, she has a problem with nerves and is perhaps under too much pressure. Honestly, to me, Nika has always been a bit of a nervous skater, and you could see it even back when she was on ice age kids, the sort of antsy expression she would have on her face at times when skating. From what I can tell, she seems to be a bit shy/introverted and has trouble emoting, so I don't think that helps.
Overall, she definitely seems like someone who would benefit from a sports psychologist