Can I install iWork on my Ventura-running iMac?

Yes. Visit the Mac App Store. Sign in with your Apple ID. Install as needed: Pages, Numbers, Keynote. The versions as of this post are all 13.2. Apple now uses the product name, and does not collectively or individually refer to them as iWork any longer. That ended in early Fall 2013.

Related macOS documentation:

Pages

Numbers

Keynote

think these days you download the apps seperatly

iWork - Apple

all should be free and work with Ventura

The last iWork '09 as a Retail Version on DVD was released March 28, 2019

Subsequent Pages, Numbers and Keynote applications are available to download from the Apple Apps Store

Once logged into the the Apple Apps Store

Just type in upper left pages as in example below

Do the same for Numbers, and Keynote

In my case, the Pages application is already installed.

So it shows Open versus Download

Omitted to offered Congrats 👍