The info from Zwift says Campagnolo N3W 13-speed chains are not compatible with the Cog. I have no way to test this personally but they have. I’m unsure what you’ll experience if you use it.
I’m just confused because we see n3w hubs on the market for a Neo 2T. But that is just the hub to allow you to fit your own 13 speed cassette.
But then with the zwift cog, I’m reading some people are using an older spare chain of 11 / 12 speed etc and using a quick link to swap them over for outdoor / indoor rides
You can use virtual shifting with a normal cassette installed on the trainer, so that’s another option that would let you run the manufacturer-approved sprockets on the trainer (with the appropriate freehub body of course). You are not obliged to use the Zwift Cog, though it does make bike swapping easier.
The Zwift Cog works with most standard 8-13 speed chains, and the 1/2 x 3/32 chain used by the Zwift Ride. It’s also compatible with SRAM flat top chains. Zwift Cog is not compatible with belt drives or Campagnolo Ekar 13-Speed Chain.
In theory 5,6 & 7 speed chains should work, we just haven’t tested this so we can’t verify the experience.