software update

All it indicates is that you can upgrade to Ventura if you so desire. It doens't mean you have to.

You can turn off automatic updates in Apple menu -> System Preferences -> software update.

To be informed of when an update is available, visit:

Apple security updates - Apple Support

regualrly.

Updates are inter-year updates that happen throughout the year to annual upgrades.

Mac OS 13 Ventura is an upgrade to Mac OS 12 Monterey. Unless you want to upgrade to an earlier update using the terminal, you will always get the last update for any upgrade on the App Store.

The terminal command for intermediate updates goes something like this:

softwareupdate --fetch-full-installer--full-installer-version 11.6.3

When it is done downloading, go into your applications folder, and be sure to rename the installer with the actual update version, as you may not know it and need it for a later time.

Not every update is available this way.

Generally, I don't install any new software unless I'm backed up, and check for compatibility with it.

A significant difference of Ventura to Montery is that System Preferences becomes Systems Settings. It is more akin to the iPhone Settings App than previous Mac OS versions.

when they change the name it's not an upgrade but a new operating system, so it does not show up under upgrades but one has to get the new version from their app store, it's a new upgrade for your mac not a new upgrade of your current operating system.

macOS Ventura - New Features - Apple

Yes, once you upgrade to Ventura, you can't change the photo library albums back to Monterey or earlier style, or Music library playlists to Monterey style or earlier. Unless you make a clone backup first.

If you make a couple clone backups with either Shirt-Pocket Superduper or Bombich Carbon Copy Cloner to hard drives larger than your existing drive that are external, you will be able to restore your Monterey exactly as you left it.

The beauty of a clone backup, even if you can't boot them, but they appear to be the right size, you can run the older installer on them after initially running internet restore to get to the operating system that came with your Mac. Then you can upgrade back to Monterey.

The naming Apple gives these systems have significance to them as place names in California, which is their home state. Before they did place names, they called their operating system names after cats.