Can't access external SATA HDD via enclosure
Your &quot;Update (GUESS):&quot; is exactly correct macOS has no (native) ability to read/write filesystems common to Linux.
Heck it can only READ NTFS file systems without 3rd party software.
Also you cant just plug a bootable Linux installation (Or Windows, for that matter) into a Mac and expect it to just boot.
It is possible to work with and install both Windows and Linux on Apple hardware. Apple offers Boot Camp software that enables Windows 10 to be installed and run. But with Linux you will have to seek out how to install Linux on your Mac.
People here on AD may be able to help you with that. There are also lots of places online (mostly Linux-centric) that can help you install Linux on your Mac. But you cant just plug a Linux disk into your Mac and expect it to be bootable. Heck you need additional software just to read and write to the disk itself.