One question I have not seen asked here. How is your external SSD formatted? All of the external SSDs come formatted in XFat, which works on both Mac and Windows platforms. XFat is saddled with numerous compromises to make it work cross-platform. Apple is APFS. If your external SSD is formatted in APFS, your Mac Mini will mount it as an internal drive. You will not get the full speed if the drive is not set up for USB-4 or Thunderbolt 3 & 4. Check to see if your SSD is formatted in APFS, if not, do so. The Samsung T-9 SSD works with Thunderbolt 4. I am using the T-7, which works with USB 3.2. I had these T-7s in use on my mini PC. They were no longer needed there, so I formatted them to APFS and installed them on the Mac Studio; one of them is my Time Machine. I highly recommend the Samsung "T" series, which uses an NVMe SSD drive.
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