At that point, why not run Pages in a VM? I feel like you're not taking advantage of that Monster iMac.Just tossing my hat in this ring... My business is dependent on Pages '09 4.3 and cannot be upgraded to a newer version. I have tried to use Mojave, but Pages, at least what I depend on, is less stable on Mojave. Consequently I'm stuck on High Sierra, apparently forever. Sure, Pages crashes sometimes, but I'm used to it by now and can generally avoid file corruption. For me, HS is clean, productive and stable. My primary computer is an iMac Pro 3 GHz Xeon - a fabulous machine - which handles High Sierra beautifully. If I could find a faster processor, I might switch, but overall I'm happy.
I have to use a similar machine at work with Parallels because I absolutely have to be able to run older versions of software. While the iMac is running Sonoma, Parallels is running High Sierra and it's great to have the capability of both at the same time. Of course you can run Parallels apps without the whole window interface. I forget what it's called but it makes it look like the App (Pages) is running right on your native desktop.