how can I download macOS 26.7.2

You can use Terminal to download the installer for compatible macOS versions no earlier than the version that came with your Mac, or the closest version still available.

softwareupdate --list-full-installers

This will return a list of all the installers that are available:

Download the latest version using the following command, in this case for version 26.7.2:

softwareupdate --fetch-full-installer --full-installer-version 26.7.2

NOTE - the full installers are large - 15GB or more.

btaylorite wrote:

Thanks! And next step after downloading?... just follow instructions in the downloaded installer? It didn't seem to actually change OS from Sonoma to Tahoe...

Launch it.

It’s usually an app named Install macOS Tahoe.app.

If you want a bootable installer: https://support.apple.com/en-us/101578