Civil War is the first film I've seen twice in theatres since Endgame. I felt there was more to look for after the first viewing left me so gutted.
There are a lot of themes to unpack. The most jarring stuff is certainly the firefights and battle scenes, but it's best digested solely through the eyes and experience of the journalists, specifically the photojournalists. Generational trauma, PTSD, disassociation, disillusionment, and so on. There's a broad way to apply that in respect to violence and war, and a personal one to the characters.
I also liked how apolitical it was:
On one hand - because I have a personal fascination with alt-history type stories - I wish the background of the war was more fleshed out. On the other hand that would completely undermine the whole purpose of the film.