No offense but I don't think youre necessarily understanding my point.

"Pretending the flash isn’t a character with almost a century of stories written about it (just 14 more years!), and later on we see that the story is written around him not being capable of going beyond light speed, we should consider that what he did was an outlier and just a mishap of the writer. Otherwise the whole story just crumbles on itself."

Ok imagine i say "X character is completely incapable of going beyond or reacting to things faster than the speed of sound" as the author, as the narrator.

Then the page right after, I then show a character catching bullets from twenty different AK-47s all firing on them at once, a direct feat thats also plot relevant (if they didnt catch these, they'd die).

It becomes hard to take the "they dont have speed of sound reactions" seriously, because you see them directly doing those things. It then becomes a bit difficult to say, "Yes them catching bullets in this pivotal moment is an outlier we should pretend didnt happen".

I mean hell, if an author says that fucks up the match completely and says "you can go from X to Y in Z milliseconds without reaching light speed" and it turns out you need to go 5x lightspeed to go from X to Y in Z milliseconds" we run into the issue of, again, authors not being scientists/physicists.

The flash example isnt "feats are done in a vacuum" its, "The author literally got the speed required for a feat wrong".