I'm having the same issues as everyone above. The Apple Store swapped my iPhone 7 with a cracked screen with a new phone five days ago. The battery starting draining excessively and getting hot on Friday night. Lots of strange issues, such as the battery not charging even though it was plugged in. Message crashing when opening.
I went back to the Apple Store and they did a new iPhone restore, after numerous hardware tests that showed my new phone was in perfect order. The tech felt that the issue was related to messages and now I come across this thread.
I've tried all of the fixes mentioned after restoring a backup again, but the issue persists. I think the only permanent solution will be for me to do another new phone restore and leave my backup off, keeping iCloud info (contacts, photos) but losing years of Messages. I would also need to download all of my Apps again, though Messages is a much higher priority.
Any new ideas out there to avoid a new install?