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.
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