It’s shaping up really nice man. Regarding the 8k texture and the 3d turrets outside I’d make sure to light them in a correct way, meaning no skylight. Light naturally bounces in space just as much as it does on earth but there’s no atmosphere to light everything evenly and generate a lot more bounces. This tends to reduce the levels of AO and definitely cuts the blue color information in the shadowed areas. For the 8k texture elements I’d much rather do just a color pass at best and turn them either in a displacement map or at least a normal bump and get the shading dynamically from your sun. At best you can consider earth to cast some lighting as it reflects it.
All the best