When you think of a USB flash drive, you probably only see it as a portable device for storing ... and select the "Dedicate this Device to ReadyBoost" or "Use this device" option.
Running Windows completely off of a USB flash drive is quite handy ... go to the "Download Windows 11 Disk Image (ISO) for x64 devices" section. Next, use the drop-down menu to select "Windows ...
Most of the newer SSDs make use of USB-C ... to your phone via USB-C, there are certain external storage devices for smartphones that work better, thanks to their portable size.