The factory installs software you will never be able to install following Apple erase install, so you’re not getting factory unless you have some image of it before you booted it the first time.

Erase install recovery has options. If you don’t want the current OS, do this:

• https://support.apple.com/en-us/HT204904

use Shift-Option-Command-R at startup to install the macOS that came with your Mac, or the closest version still available.

Catalina is still signed so I must conclude your reset procedure is different than the one above. Let me know if I missed anything relevant. Good luck with the next reset - there are many ways to get Catalina installed but the above is the easiest for me and well supported by Apple if needed.

The factory installs software (Garage Band, iMovie, Pages, Keynote, Numbers) in an unregistered state and you will never be able to install that license/state following Apple erase install.

So no one is really getting factory unless you have some image of it before you booted it the first time (and Apple honors the license claim a second time).

Erase install recovery has options to get you close to several versions of macOS if you didn’t clone the drive - documented here:

• https://support.apple.com/en-us/HT204904

use Shift-Option-Command-R at startup to install the macOS that came with your Mac, or the closest version still available.

Catalina is still signed so I must conclude your reset procedure is different than the one above. Let me know if I missed anything relevant. Good luck with the next reset - there are many ways to get Catalina installed but the above is the easiest for me and well supported by Apple if needed.