Not sure how that disputes my point? If you face 20 shots per game, each from a poor position with an Xg of 0,2, you still get a very high xgc. The other issue is that as several articles point out, another issue with xgc being accumulated is that it doesn't factor in the rest of the team. Lloris went from one of the best in terms of xgc to one of the worst, to much improved. The reason was mostly down to playing style - a high line meant he had far fewer shots to save, but the ones that he had to make were very difficult, often one on ones, which one would not expect him to save, but due to them being accumulated, he finished the season with a low xgc. Subsequently, facing 20-25 poor-ish shots every match can provide you with an infalted xgc.
I'm absolutely not a statistician, and thus I do not pretend to know how these things work all that well, and use of stats is quite advanced and multi faceted. Context is very important when discussing stats. Saying that Onana had a very good Spring last season is a stretch - he was good, but still he lacked reach and let in goals that you would expect the best goalies to save. This was further discussed by goalie coaches and ex-pros. This season, he's been very good. One game doesn't change that. One of the best goalies of all time, Schmeichel made some huge blunders - it's how you bounce back.