They are not the same. system_other.img contains app and priv-app vdex files. It is not a complete image. All the app and priv-app apk files are in the system.img. When you combine the 2 you get a complete system. It is possible however, that your device uses system_b to store the vdex files and system_a for everything else. This is not how most A/B devices work though.
Woah, that is complicated, according to rawprogram0, its labeled as a/b
That is really interesting to hear, i would have to combine them again with rawprogram0 in the morning and see for myself.
btw this device is really complicated, i soft bricked yesterday and couldnt fix at all, even after flashing the full qfil ROM, i might end up with expensive paper weight, i was able only to boot up two different GSI ROM on both slots a/b