Not the OP, but PCIe5 NICs are already available in the market; I've seen people requesting help getting them to work on desktop platforms which have PCIe5 as of the most recent chips. AFAIK, currently, both AMD and Intel release desktop before server; I don't think there's a public release date for Zen4 server chips, but probably this quarter or next? Intel's release process is too hard for me to follow, but they've got desktop chips with PCIe5, so whenever those get to the server, then that might be an option too.