The video is about a 2x1 link, which the author hopes to eventually scale up to 3x4 using 40 gig transceivers. I'd say thunderbolt is probably safe in the near future.

Easy, fs.com has 1.6Tbps OSFP for about 570€ - though only up to 1m lenght apparently.

That's 64Gb per lane across x16 lanes. That sounds not daunting?

There's already 800Gb transceivers readily available, 1.6 is probably getting preview deploys to some hyperscalers & other early adopters as we speak.

Bidirectional is a lot like biweekly. Biweekly depending on context means twice a week or once every two weeks and bidirectional can both mean per direction and total of both directions.

But yes I meant 512Gbps each way, to be clear.