Update! I managed to trick it. Here's what I did, in order.
On the site's hub page, i changed the name of the original page to gallery1 and it's slug.
In Hub's content library, I removed the cloned page from the initiatives content group.
In AGOL, I changed the Name of the cloned page to 'Broken'. Not even sure if this is necessary. I reshared it to the initiative's content group from the item detail page.
I went back to the Hub manager and linked to existing content, page= Broken. It then allowed me to update the name and slug and finally showed under the list of pages for the site. It also finally allowed me to publish without error, which saved me from redoing all my work. Lastly, I'll edit the original page to delete the "1".
This is obviously not a great work around and doesn't not fill me with confidence that cloning is a tool that should be used....but it might be a one-time saver for someone like me who didn't want to redo the finished page.
Cheers,
Beth from University of Richmond