It sounds like your home page may have gotten borked in this process. I can’t think of a way to fix it aside from rolling back to before you made the new home page. You should be able to contact your host and see if they can roll you back from a DB back up. It sounds like when your updated the home page options may have been set in the customizer or some where else and that’s more than likely what’s breaking the display on your old home page.
So sadly, rolling back might be the best option. It would mean you would lose all current progress, which is no fun. It’s possible I’m wrong and maybe someone else will correct me, but if I were in your shoes that’s where I would start.