The invasion scene in Zack Snyder's Justice League (2017) is arguably one of the best scenes of the film - in my opinion though, the best scene out of ANY comic book film. It appears that there were scenes also cut from it. ScreenRant is reporting that the flashback invasion scene was suppose to include Ares and Darkseid battling it out in an epic showdown, a sight I'm sure everyone would have liked to see.
It's likely that the scene was removed rather early in the production, when Darkseid was removed as the primary antagonist and replaced with Steppenwolf. 'Justice League' received a massive overhaul in design and tone over the course of its development and production, mostly due to the polarizing reception to 'Batman V Superman: Dawn of Justice', and fans are still not over it - I know I'm not.