Yes a few sides characters. The Dothraki & Unsullied aren't even characters.A few side characters? The entire Dothraki army and a huge percentage of the unsullied died as well, that's going to mean something going forward. I'm also wondering if her dragons are going to be compromised a bit because of all the punishment they took, we can already see Rhaegal has holes in his wings now.
Taking Kings Landing without killing everyone in it would always have been a challenge, she was trying to avoid that and of course doing that first and allowing the Night King and his army to work their way down to Kings Landing and continue to grow would have spelled doom for them all.
As I said already, the Night King was just a way to even the actual big fight. This shouldn't even be debate, it is so obvious.