I'm surprised that you have to use a second mac to "revive" it. I had always been impressed that at least the intel models could always bootstrap themself and go online and download their OS image. Even with a new blank drive installed.

Not a mac user, but is there really not a bootable USB at the very least that you can use for this rather than needing another Mac?

That would be a cinch with a Mac one decade ago, or 20 years or 30 years ago, or probably even back in 1985.

But these days, when it comes to external bootable drives, Apple vacillates between neglect and hostility.

I've lost track of the current status of bootable backups on the Mac. Based on the following blog, it seems there's some new insult to the process once or twice a year: https://eclecticlight.co

I'm still trying to understand if these NAND chips are proprietary and if so where vendors are getting them.

Those arent NAND chips. Those are proprietary PCIE SSDs packaged in BGA chip form.