The review below shows a drive which supports both TB3 and USB 10Gbs.
Even for very heavy random reads which use less bandwidth than 10Gbs offers, in USB mode the performance difference is 113 v 422.
This probably highlights the underlying issue which is that the NVMe protocol is important to maximize random I/O on PCIe drives.
The move from SATA wasn't just at the physical transport level, but also at the higher protocol level from AHCI to NVMe.
For sequential I/O, the bottleneck isn't the lack of NVMe but the raw bandwidth.
So even with USB 40Gbs, for random I/O, it's probably not faster than USB 10Gbs.
For random I/O, the drive in the test below in USB mode tops out at 465MBs which is not much more than 5Gbs.
So if you want to get close to an internal drive with demanding workloads, you need TB3.
This begs the question as to whether USB4 encapsulates PCIe/NVMe?
Also, do Apple even use NVMe on their internal AS PCIe SSDs.
I think not.
SanDisk Pro-G40 SSD Review