What if, instead of an actual carrier, it built a repair ship equivalent? Something like a fighting repair guardian? It'd be about the equivalent of say, 500 ships, but could be priced by what it 'ate' to create itself. It could even use the existing modular mechanics, allowing for a stronger version based on what it 'ate' to come into existence. Treat it like a real 'carrier' instead of just portable armor.
This idea, however, might not be as valuable. When I was dealing with some massive waves on an 8 homeworlder, I'd get 5-6 carriers packing over 4000 ships between them. That's a massive removal for waves, so they'd have to be worth the replacement.