Considering your 93MB/s acheived with a rockPi 1Gbps Eth and USB3, I don't see how Orange Pi or RockPi S can even compete. The limiting factor won't be the USB 2 interface but the 100Mbps Eth interface maxing out at 12 MB/s. If we would have a 1Gbps Eth and USB 2 we would get above 30MB/s as the USB 2 maxes out at 60MB/s theoritically.
Do you have any other experience with board having 1Gbps and OTG?
I would like to find the best ratio between performance and consumption.
In my opinion with either of them, it will take a few seconds to load a game. You asked about performance and cost. If you want performance go for the Rockpi. If you want to save money get the cheaper one. Both will work. Don't get a raspberry pi zero, it wont.