Updating Rooted TWRP installed phone question

I used the flashfire method of downloading firmware and extracting ap file and flashing system and boot.img. Does anyone know or has anyone tried taking the ap file and extracting system.img and boot.img and flashing those image files via twrp? Twrp I believe supports flashing image files and that should work in theory. Thanks
Also is it important to update csc or csc_home files? I am learning Samsung coming from always owning nexus devices which are quite a bit different.