startup – Unable besides macOS from an exterior gadget on MacBook Professional M3

I’m making an attempt to put in macOS 15.0 (24A335) on an exterior reminiscence gadget and boot from it on my MacBook Professional with the Apple Silicon M3 chip that runs the identical construct on the inner SSD. Right here’s what I’ve finished to this point:

1. Initialized the exterior gadget with a GUID partition map
2. Created an APFS partition on the gadget
3. Downloaded the macOS 15.0 (24A335) installer straight from Apple’s SWCDN
4. Ran the InstallAssistant.pkg and obtained a duplicate of Set up macOS
5. Launched Set up macOS and put in the OS on the exterior gadget

All the things went easily up so far. Nonetheless, after the set up:

• I attempted choosing my exterior gadget because the startup disk and restarted the pc, however I acquired the error message “The model of macOS on the chosen disk must be reinstalled.”
• I booted into restoration mode, and my exterior gadget appeared within the listing of bootable disks. However once I chosen it besides, after some preliminary loading, nothing occurred.
• I additionally chosen the gadget because the startup disk from restoration mode, however once more acquired the identical “The model of macOS on the chosen disk must be reinstalled.”
• I made certain that my Startup Safety Utility settings are set to “Diminished Safety” and that the gadget’s data on Disk Utility exhibits “bootable: sure”

I’ve beforehand put in and booted numerous working methods on my older Macs and PCs with no points, from unsupported macOSs to Home windows and Linux distros, due to the abundance of boards and guides on-line. This time, I’m struggling to search out anybody with an identical subject, and there’s little or no data out there. One web site briefly mentions that “It is not as straightforward because it was once, because it probably requires you buy new {hardware}”, but it surely appears to seek advice from needing a USB 3.1 or larger exterior gadget, which I examined with a USB 3.2 pendrive with out success. One other weblog even offers a tutorial on “The way to Boot Intel/T2/M1/M2/M3 Mac from Exterior Drive”, which suggests this ought to be attainable, however I haven’t had any luck. I learn another issues round, reminiscent of naming the gadget with no areas and altering the USB port to plug it into, however nothing labored.

I’d want besides macOS from an SD card within the built-in SD reader (for minimal muddle, even when it will be sluggish), however I’m open to purchasing a brand new USB or Thunderbolt gadget if it ensures success.

Has anybody encountered an identical downside? Any options on tips on how to resolve this?