I would offer that the premise of the game has to be a given to explore the worst case scenario. I would also offer that the result being a bloody stalemate in which the invasion fails is a piece of information designed to influence China to seek alternate means. ("If the Americans are thinking this will be a win albeit a bloody win, maybe we should try to figure out why they think that")
If China hasn't also been doing these games they are foolish. Now, i note that the most popular advanced simulation for the general public is this thing called DCS which has all sorts of videos on youtube which always portray Russian systems as being 10 feet tall. Why? Because its a company run by Russians (out of Switzerland). When you watch these games they always include things the Russians clearly don't have ready (SU-57s). I think any sober individual who has watched the past year will revise their estimates at Russian Air Force effectiveness. Likewise, until China actually has to engage in air-to-air combat they might be advised to temper their expectations on what they can accomplish.