(error code 110)Mount of outer dmg failed.

This issue has been raised before and the low hanging fruit response is: try a different USB and download new copy of installer. I have done both of those things to no avail. I am attempting to create the boot disk on a Macbook Pro with Sonoma 14.5

Is it possible to create the boot disk for OSX El Capitan on this machine and OS? I have followed the instructions found here: How to download and install macOS - Apple Support

The process is successful up until the point where Terminal says "making disk bootable" then fails.

Thank you for your time and advice on this in advance.