How do I revert to an older version of Pages and remove the suite of apps?

Pages, Numbers, and Keynote are individually installable and removable applications. You select the application and just move it to the Trash, followed by emptying the Trash. Removing one does not impact the others. Don't do this without planning though…

At present, the oldest version of Pages you can obtain from the Mac App Store is v15.1.1. I see no win in deleting Pages v14.5 and then restoring Pages v14.4 from a Time Machine backup, provided you have one. There will be no future updates to the Pages v14 series after v14.5, and v14.4 may not work properly on future releases of macOS.

At present, I have Pages v15.1.1 installed on Tahoe 26.3. It does not automatically subscribe you to Apple's Creator Studio. I am satisfied with its ability to open older Pages documents, and its created documents with older versions of Pages on my other Macs.

Since I do not subscribe to Apple's Creator Studio, and hence, have no means to unlock the premium features in Pages v15.1.1, I cannot make any assumptions about the backwards compatibility of premium feature documents to older versions of Pages.

If you have a Time Machine backup, you could delete the 14.5 version and restaure the 14.4 version.

I'm not sure what you mean by removing the suite of apps as I haven't installed Apple Creator Studio. ( I do have Pages 14.5 installed, though.) I suppose the suite would be uninstalled the same way as any other app by moving them to the trash.