I have mentioned this before about Ilia and maybe it is something worth repeating.
Performance anxiety is tricky. I believe that Ilia created this problem for himself because he is always chasing. He gives himself these challenges. For instance, landing all different types of quads in one program. Landing the first 4a-3t combo. Landing this or that new combo.
I don't know him, but sometimes performers who do set such challenges for themselves are also the kind who are looking for perfection in a performance.
I teach my kids this : do not go for perfection but for excellence.
What is the difference ?
Perfection means that after a mistake is made, the performance is then flawed. Confidence drops. The performer gets in their head and makes even more mistake. At the end of the performance, there is a feeling of WTH just happened ? It's all a blur. This happens often with figure skaters because of the "being clean" concept. My first skating love, Josée Chouinard, is perhaps the best example of a figure skating talent that never got fulfilled (it did in the professional circuit later on) during her career. Even commentators picked up on it : if Josée landed the first jump, then she had a good chance at a good program. As soon as there was a mistake, she would collapse. The pressure of perfection is what I believe killed Ilia's LP.
Excellence is trusting your training. Excellence is about a global level of performance. Not about every detail. In my field, micro mistakes happen all the time. Not only playing a wrong note, which is considered a bigger mistake but mistakes can be made many other ways : wrong touch, too much or too little sound, too much pedal, wrong attack of dynamic, wonky phrasing, missed opportunity for a colourful moment, etc etc. These are often not even perceptible by most people but are mistakes a perfectionist may get sidetracked with. Thinking about perfection is a recipe for failure because it makes the performer become self aware and judgmental about every single detail of their performance, leading to increased anxiety. A performer focused on excellence will look at things more globally and manage to avoid this increase in anxiety.
I believe that unfortunately, the approach Ilia has with competition, is probably closer to "perfection" than "excellence" with all the challenges he is setting. Too many ultimates. Too many challenges... too many records chased.
Also, even when a perfectionist performer succeeds their elements, often, this approach isn't as free. This is how, sometimes, an excellent performer can even surpass a perfect one as their performance breathes better.
Sorry for the long post

. Perhaps it does explain how Ilia felt... I cannot confirm what goes in his head obviously but from how the events have unfolded, I thought I'd make this suggestion...