external boot drive

I'm trying to create an external USB SSD bootable Ventura drive and having no luck. I have partitioned my external SSD with a 40GB Mac OS Extended partition and the remaining 470GB as APFS.

Using the Apple doco here Create a bootable installer for macOS – Apple Support (UK) the "Install macOS Ventura" pkg successfully installed onto the 40GB partition and I then booted from it and started the OS install to the 470GB APFS partition.

At the 28min mark the process stalls for a few minutes and then fails with "An error occurred preparing the update. Failed to prepare the software update. Please try again"

No amount of trying again succeeds.

I also tried cloning my existing OS to the external SSD using SuperDuper which appears to succeed but when I try to boot from it it fails and eventually boots back into the Macbook drive and displays a Kernel panic error.

I should mention this a 'new' refurbished Macbook Air M2 from Apple direct (3 days old) with 24GB RAM and 1TB internal SSD with no other issues or problems thus far.

I'm at a loss so any help appreciated.