I mean, it was a fucking lot and was the most cringe scenes too.
All Whedon reshoots:>The "what is brunch" gag when Bruce recruits Flash >Flash messing with the Batmobile when he first went to the Batcave ("woah it's like a cave...a Batcave!!!")>Batman encouraging Flash to save one person>Flash faceplanting in Wonder Woman's tits>gravedigging/"lmao Pet Cemetery">Superman helping Flash evacuate the village>Flash's interludes with the Russian family>The Superman/Flash race
There was also numerous other character-driven scenes for Flash in Zack's Justice League, especially a time travel bit at the end of the movie where he gets a new suit. It seems like wasn't a total loser, just a little awkward. He had a fucking girlfriend. It was just a totally different character than what we got.