Oculink isn’t, and won’t be rated for PCIe 5, though I’m sure you’ll see a lot of folks try and pray. CopprLink is the successor to get back to 2 Meter external run support, but its connector is going to be much thicker than Oculink.
For now though, in the consumer realm that’s really only the NVIDIA 5090, and the difference between PCIe 5 and 4 is negligible at x16 (but measurable at x4). Still, folks in this thread have been constantly jumping between saying they need support for the fastest GPUs available without speed impact, while also saying they need to be able to support hardware from eWaste systems, so there’s a broad spectrum. For those on the bleeding edge, OCuLink is not really going to be able to support future flagship GPUs without further compromises. USB4 v2.0 will exceed OCuLink’s capabilities by the same degree that OCuLink exceeds USB4 today. But if USB4 is anything to go by, we’ve probably got another 1-2 years before we see an ecosystem mature enough to deal with it. Intel’s own Thunderbolt 5 (since that’s the closest you’re getting to seeing USB4 v2.0 in the wild right now) has had a fairly shaky start.