Most modern SSD's running over a USB 3.x or USB 4.x (USB-C) or Thunderbolt connection are fast enough to handle 8 stereo tracks or 16 mono tracks (or more) of recording.
Consider using Avastor or OWC brand drives which are designed for the broadcast and recording industry.
Unfortunately most of what you find in a modern electronics or big-box store is inadequate for real-time audio recording. USB 2.x external drives or devices that have spinning hard drives with a rotational speed of 5400 RPM or less where you will run into problems. These older slower technologies are designed for energy conservation. These types of devices will result in "Disk Too Slow Errors"
Stay clear of the inexpensive drives, these most often have spinning hard drives with 4200 RPM or 5400 RPM drives in them. Even some of the larger multi-terra byte drives that seem like a good deal also have slow spinning drives in them. Unless it specifically states that what you are getting is an SSD or m.2 type technology, probably a good idea to stay away from it.