NEBULOUS: Fleet Command - The Carriers Update.
Wow! There is an enormous amount of new stuff that has been added. Carriers, fighters, utility craft, smaller craft, more of the previous sized ships, and countless other changes.
If you want Expanse style space battles, this is it.
In the future, I'm curious if the boarding units will be elaborated upon.
There is an older demo available on the Steam page, by the way. It might or might not be missing quite a few updates and improvements, though.