Main gray texture kinda just makes it look bland and take away from what it's meant to look like. But idk what you could do to change that. Making the checker pattern the main texture would be too busy, and I can't think of something that could replace it.
I'm sure you can improve it, but I feel like the concept itself kinda reaches a dead end at just being okay.

don't use saturated black and white

Scaling problem, yeah, but is complicated since each individual weapon uses different scaling so the only way to properly fix it is with custom coding and mapping

The checkered pattern looks a bit weird on some weapons and perfect on others. Not exactly sure if that can be fixed. Maybe scale the texture up? I don't know.

concept and color pallet is nice but checker war paints never look quite right in the game, sorry

yeah plafon fan is right

You should scale up the primary texture.
That way it would look much better.

Virgin football fans
Chad soccer kings