Thunderbolt/ USB 4 vs Thunderbolt 4

One thing required for a computer to get Thunderbolt 4 certification is for it to offer the ability to drive two displays over USB-C (DisplayPort) or Thunderbolt.

If you study Apple's Technical Specifications, you will find that

• Every Apple Silicon Mac that can drive at least two such displays, without turning off any built-in one, has either Thunderbolt 4 or Thunderbolt 5.
• Every Apple Silicon Mac that can drive only one such display – or that forces you to shut off a built-in display to use a second USB-C or Thunderbolt Display – has Thunderbolt 3.

You will also find that every Apple Silicon Mac has USB4 ports, and that no Intel-based Mac does. The first Apple Silicon Macs were either the first machines, or among the first, to implement the then-new USB4 standard.

Thunderbolt 3 has 16 Gbps of bandwidth and Thunderbolt 4 has 32 Gbps of bandwidth.

see > https://www.owc.com/blog/whats-the-difference-between-thunderbolt-3-and-thunderbolt-4

and > https://www.intel.com/content/www/us/en/architecture-and-technology/thunderbolt/thunderbolt-3-vs-4.html

Note that the Macs with the M4 Pro chip have Thunderbolt 5 ports with 80 Gbps for bidirectional transfer and up to 120 Gbps with Bandwidth Boost, which is double that of Thunderbolt 4.

What about them?

USB-C, Thunderbolt 3, Thunderbolt 4, USB 4 all use the same connector and are backwards compatible.

The only real difference, is the total number of bands (paths) that are offered.