Hi,
yes thats a very good question.
A realistic space game scenario wouldnt working. That would mean an enormous space that the engine couldnt handle.
But there is an easy solution that you can already find in games like eve. Make everthing ultra small (like you’ve said :D)
For example: I have found a configuration file in the game “homeworld”. Maybe you know it. In this file you could see the speed of the ships. For example 300.
Obviously that means 300cm/s. Thats not fast, but if you make everything smaller, it feels realistic.
I dont know if you can use this for planets cause of the gravity. I think you would get an unrealistic result, but its fine for space.
Hope that helps a little bit