Looks grim. Could only be for the 16 lanes of CPU Graphics PCI-E anyhow. Z490 chipset PCI-E would still be the same PCI-E 3.0. And Intel DMI would be the same bottleneck.
You think about it. You can run graphics cards on 8 lanes PCI-E 3.0 instead of 6 with little impact to performance. So If you are running the graphics card with 16 lanes you should be fine even with the 30XX cards.
Only place it would matter performance-wise if you are using 8 lanes of the CPU graphics PCI-E for an nvme SSD.