While Thunderbolt 3 could be the same as USB 4[*], USB 4 is not the same thing as USB-C.
And then there's also Thunderbolt 4.
* - it is really not. While USB4 is based on TB3, it made some TB3 parts optional. For example, USB4 is required to support 20 Gbps at minimum, while TB3 does 40 Gbps for all implementations.
For computers with USB-C only the situation is more complicated.