The kernel is telling me that PCIe bandwidth is limited
Solution 1:
It is because your system/bridge doesn't support PCIe 4.0 which is 16GT/s. Your card supports PCIe 4 though...
sudo lspci -vv -s 0000:16:00.0 should show you what the bridge is capable of. This will indicate a x16 link at 8.0GT/s.