Can I access system files without TWRP or root on an H990DS?

[p7810456]

I have an LG V20 H990DS that I want to modify the build.prop file on. This would usually take rooting but judging from another thread, that is very complicated and will make a red triangle show up on every boot, among other problems. Would it be possible to do this using adb backup with the system flag and then restoring it after all the changes are made, or is there another way. Thanks in advance!