Night Dimension

There are 2 ways you can do this

1. Make a check that checks if it's day in the dimension and then changes its time to night

2. Just remove global lightning and sky light source it will be forever dark but I do believe that the sun still rises

There might be other ways to do this but none that I know off

When time = o st time to night but this will also acelerate time passing

Sun always rises, make it black coloured sky, better than nothing

Don't change the time using command because this change time in the Overworld too. Just remove global light and set the sky color on black. If you want stars read custom sky tutorial by MrScoutHD

https://mcreator.net/plugin/93491/custom-fog-plugin-forge-1182-1192