The interface with the highest throughput is the SDRAM interface. You can use an FPGA connected to this interface and convert it to gigabit ethernet. But I assume that this is expensive and and a lot of work.
The SGPIO interface is also pretty fast if you configure it for a 16-bit parallel output, this would be on the FPGA side a little bit easier to realize, but also here you have the cost and the development work on the FPGA side.
Then comes the LCD interface, 24-bit wide, also a relatively high throughput when you clock it on 50MHz.
Regards,
Bernhard.