@variablepulserate I checked my archive of macOS versions right back to Tiger, 10.4. One was missing: 10.13 High Sierra. As my M1 Mac Mini is too new to install that version, I have used my 2017 4k iMac to perform the download and used AirDrop to transfer it to the Mac Mini.
I had to do the latest Ventura update on the iMac anyway.