So, I did the dumb, I erased the HDD on an '09 iMac (El Capitan) without verifying that the third-party-created thumbdrive installer (DiskCreatorX) actually worked as a bootable drive on the machine. Turns out it didn't, and then I ruined it anyway by trying to change the partition size/filesystem type from 64 GB OS X Journaled to ExFAT 12 GB (I'm not sure why on earth I thought that would work and not erase the partition.. duh).
Now I have an '09 iMac (iPaperweight) with no OS, and it won't let me download OS X from the App Store through recovery because apparently that's no longer available (?).
But.... I have a brand new iMac running MacOS Monterey.
So... How do I create an OS X El Capitan installation media from an iMac running MacOS Monterey? The new iMac won't run the El-Cap installer package inside the .dmg because of machine incompatibility. I'm sure there has to be some little-documented way of actually accomplishing this... (also feel free to throw a virtual tomato at me for being dumb.)
