Pages file overwritten after OS update

I have been working on a shared Pages doc for some time (updating a holiday itinerary) and at some point my computer decided that Pages (or my OS, or both) was too old for it to be shared/collaborate online, so I continued to make changes offline. Yesterday, my Mac updated to Ventura 13.7.3 and the Pages file has now been overwritten by a much earlier version (I'm assuming this is that last version of the file that would upload to iCloud). When I go to 'File > Revert To' the 'Browse all versions...' is greyed out, so I can't restore. Why did it do this!? Is there any other way to recover the file?