MagnusPrime I don't consider correct time format display a cosmetic that's a core functionality to be able to tell time right according to the format of the region you are set to.
Ok.
I don't really like the lockscreen clock behavior myself, but Google really does change the lockscreen code frequently, which probably would lead to merge failures.
I don't speak for the GrapheneOS project, but I suspect they are more likely to spend developer time on things like VPN leaks, Android 17 glitches with Bluetooth and Android Auto, etc., than on lockscreen time formats. On the other hand, since it seems that the developers are all over the world, maybe somebody will look into it this week.