ARM boards with slotted RAM use the same type as x86 (although mostly LPDDR, as found in laptops), so I assume there isn’t any difference that is related to the CPU architecture.

My theory for why it created copies: The files you listed look like they are all subdirectories from /dev, which is (usually) a separate filesystem. When you try to move a file or directory across filesystems, the OS can’t just change the link, it has to actually copy the files and then remove the original. As a directory is a set of links to files, and the copies are different files, directories are just newly created with the same name in the new location instead of copying the directory filesystem entry. It looks like mv creates these target directories, before it checks if it actually has permission to remove the source, but checks file permissions, before it copies them

Except the circumstances in which they run on gasoline are not that exceptional: https://theicct.org/publication/real-world-phev-use-jun22/ And the lower weight of the battery is partially offset by needing an additional drive train, a transmission with multiple gears (purely electric cars usually have fixed transmission) and other smaller parts required for the combustion engine. These also increase the required maintenance a lot (e.g. requiring oil changes).