Finding anything that's not hundreds of dollars to go from Thunderbolt to actual PCIe slot or M.2 slot is tough though.
There are a couple solutions, but then you have to have hardware that has a Thunderbolt port as well... and those aren't everywhere, especially on cheaper computers and SBCs.
TB4 is PCIe over a cable. USB is out of the picture after device initialization.
Finding anything that's not hundreds of dollars to go from Thunderbolt to actual PCIe slot or M.2 slot is tough though.
There are a couple solutions, but then you have to have hardware that has a Thunderbolt port as well... and those aren't everywhere, especially on cheaper computers and SBCs.
By "USB port alternative" they surely mean alternative accelerators that connect over USB, not alternatives to USB ports for connecting accelerators