Before writing your stupid conjectures without any evidence, you need to know what happened from February 2020 till last year. And, only for explaining that your conjecture is totally a nonsense, Julien trained in Kenya also before BAD performances. This time he went Kenya from the beginning of October, staying Europe few days only for his competitions (Escalade and ECCCh in December, 10 km of Valencia in Jan and Napoli HM on 27th Feb, coming from Kenya 2 days before the race and going back the next day).
So, your stupid and unfair supposition already start with a fake fact : that he didn't train in altitude when ran bad competitions. We need to search the reason is in some other field.