Conversely, the last time I checked a couple of weeks ago, it was impossible to find any USB4 external SSDs on Amazon; only USB 3.2.
If Amazon is a strict requirement, then this won't help. But if you're ok with AliExpress then it's probably a win:
https://www.aliexpress.com/item/1005008555989592.html
I have one of these, though I'm using with a USB 3.x port as that's what my desktop has. For me it's working fine, and for others with actual USB 4 ports it seems to be working properly for them.
Really? I see plenty when I search for 'usb4 nvme enclosure'
Wouldn't it be better to just buy an M.2 NVMe adapter, eg. ICY DOCK ICYNano MB861U31-1M2B[0]?
[0]: https://global.icydock.com/product_247.html