Sure, it connects via thunderbolt, but it's still just a SATA style SSD (max speeds around 550MBps). I'd love to find an external M.2 to get 1200MBps via external, but this seems to be a unicorn still. Although, I'm still happy to have 550MBps on a SATA SSD vs 110MBps via platters.

Here you go, 3412MBps (read) and 1884MBps (write) for the Samsung X5: https://www.techradar.com/reviews/samsung-x5-portable-ssd

Granted, it's a heck lot more expensive at 1TB for $700. It seems the only reason for this drive to exist is actual transfer speed because in any other way seems worse than the T5.

If you want USB, forget it. The best you'll get from a USB 3.1Gen2 > NVMe case is about 1GB/sec.

If you're willing (to pay) and able (to plug it in) to use Thunderbolt 3, there are several commercial products that use an NVMe internally and boast up to 2500MB/sec.

I have one of those drives - it's not Thunderbolt, just USB 3.1 gen 2.

It's also not a 2.5" drive since it's obviously smaller.

Oops, that's on me :)