It's impossible to do well all the time. And 'doing well' is relative. Of course it's about setting goals and pacing oneself. And yes, Nebelhorn is an early season competition for Mariah and she didn't necessarily lose ground placement-wise. However, the judges are making their assessments of skaters' consistency under competitive pressure whether consciously or unconsciously at every competition. Politics is always at play, so it makes it easy for the judges to keep a skater down politically even when they skate well and everything is fairly even with other competitors, if they are seen as inconsistent, or subject to faltering under pressure.
Frankly, I don't think Zagitova, Mihara, or Hendrickx are overall better skaters than Mariah Bell. Zag has the rep, cred, political backing and hardware, but she's not more talented physically or artistically than any of her competitors. In this tough, political sport, if you want it, you gotta step up and grab it. That doesn't mean not ever faltering in competitions over the course of a season. It does mean learning from every outing, knowing what you want, addressing weaknesses, enhancing strengths, being strategic, and taking full advantage of opportunities.
If it's just about the cardio for Mariah, fine. Put the cardio in then. When push comes to shove down the line later in the season at a penultimate moment, and dealing with her nerves hasn't been adequately addressed by Mariah, what will the excuse be then? Hopefully, that will not be the scenario. Hopefully, this will be the learning experience and wake-up call that it should be for Mariah. Skating relaxed and going clean in the sp, the judges gave Mariah good marks. So she should figure out what she needs to do to be more consistently competitive in both programs, under pressure. This was not a terrible outing by Mariah, but anytime I see hesitation on jumps and popping more than one jump in a program, that's not just about needing more cardio, IMHO. There's nothing wrong with mistakes happening. But there are nervous mistakes and there are 'going for it' and coming up short mistakes that are not related to nerves. Battling and winning at the next level requires figuring it out. If Mariah wasn't able to 'go for it' the way she wanted in the fp chiefly due to feeling she lacked enough cardio, then I suppose time will tell and everything will be revealed in time.