It seems that the gist of the article is "If you’re trying to create and use a bootable external disk for M1 Macs, I therefore recommend that you don’t waste your time discovering which USB-C SSDs might be compatible: go straight for a Thunderbolt 3 enclosure".
Even with that the author makes it sound as if it is a less than perfect procedure.

On a Mac since 1984.
Currently: 27" iMacs, Macbook Air, macOS 10.15.x,; iPhones, iPods and iPads galore!