What happened to the CD template in Pages
when I create a new document in Pages and look for the templates I discovered the regular CD templates are missing as well as the ones I created and saved. Where did they go?
iMac 24″, macOS 15.2
If you created custom templates in Pages '09 or earlier, they would be normally stored in the following location, where the tilde (~) represents /Users/user:
~/Library/Application Support/iWork/Pages/Templates/My Templates
The first installation of Pages v5 through v14.3 would automatically convert these older Pages '09 templates into the newer Pages templates located here:
~/Library/Containers/com.apple.iWork.pages/Data/Library/Application Support/User Templates
Because the newer Pages is not based on the older Pages '09 source code, not all features from the older Pages were implemented at all, or in the same way. Thus, some older templates where this incompatibility exists were not migrated by the newer Pages. That may explain why your CD Templates are now missing. Pages '09 supported a template folder hierarchy and the new Pages does not. That might have also affected the CD Template migration.
Another factor is that you may have saved your CD Template outside of the expected Pages template location. It would not get migrated to the current Pages. If you can locate that template, you might try opening it in Pages v14.3 and see if it works. If it opens, do save it as a new Pages template.