Comment by JK-Swizzle

Running some quick numbers shows you should be able to get >1Gbps. But I seriously doubt you could get those speeds in reality. You would need to get them perfectly in sync, which would likely take a dedicated board and some great knowledge of the oscillator.

As someone who has done a reasonable amount with PIO, I do not think this is possible. However, that should not stop you. If you get it to work, please ping me.