Wouldn't be very difficult to add a fuel cooler inline on the return to the tank.
The right thing would be to build these kits properly so the cp3 doesn't return so much fuel...
As I said earlier, pull the trans apart clean and inspect everything, new pump, new converter.
Very few do this but I always put a pressure gauge on to verify pressure after install and typically on the test drive.
Unlikely, I'd be prepared to replace the pump and converter as well as a refresh to clean all the metal out. If that was the case.
There is also a possibility that the pressure regulator valve stuck