Larry O’Conner, CEO of Other World Computing (OWC), wrote a helpful explainer about the differences between Thunderbolt 4 used by Apple and Thunderbolt 4 used by PCs.
You see, Thunderbolt 4 finally promises PC/Windows users all the features Thunderbolt 3 has long offered Apple users. For Mac users, full Thunderbolt capability has always been present. This has been true since the first Macs with Thunderbolt 3 (Thunderbolt USB-C). What Apple did was simply call out that they now support USB 4. This is in addition to the Thunderbolt features already standard and present.