The Librem 14 has a integrated 1Gb ethernet adaptor, no 10Gb option. The librem 15v4 doesn’t have any RJ45 ethernet, the only option is to connect one through USB. USB has a 5 Gbit/s theoretical maximum
None of the Librem laptops (AFAIK) have Thunderbolt. See e.g. Librem15v4 USB-C for Thunderbolt 3 Data Transfer
So I don’t think so. Unless it’s possible to fit a 10Gbit ethernet adapter in the M.2 slot.