I have the asus x570 ProArt and that has thunderbolt 4 onboard for IO, if your board has the TB header (some asus boards do) then you can get the asus pci-e card for it.
Yes. You need special headers. Some AMD motherboards have them, but don’t have official support for thunderbolt. (It mostly works though) but I’d your board doesn’t have TB headers, you won’t be able to use thunderbolt.
Has anyone else noticed that the new Z690 boards from both Asus and Gigabyte with Thunderbolt 4 support built-in, has no Display Port in available on the IO panel? I’m curious why this is the case and will this make TB Docks completely obsolete for anything that isn’t a Mac?