It needs to be done in the code.
Is it possible that they can add it in the next traccar 5.5 update?
Depends on what you mean by possible. Of course it's possible, but we have a million other things on the roadmap, but the only way to get this into the next release is if you can contribute it yourself or sponsor the implementation.
HI,
is posible, add default "device time" in device info on map, in all user.
attached image for reference
https://ibb.co/jGdr9fb