I would do the following:
- don’t publish the actual site so that you can keep a reference of the published one
- duplicate your site to keep a copy and reference of the styling and content of the last version of the site
- go back to the original project, and cmd+s (ctrl+s) to be sure to save the current version, name it “last version”
- go to sites settings, revisions, and try to find a version that matches what’s currently published, use the “preview” feature to load and check many versions
- restore the exact or closest version
Doing that, you have lost all newly designed things. Style, content, everything is restored to the version you went back to. That’s why the duplicate site is necessary to have a reference of the changes, if needed. unfortunately they can’t be copy pasted cross sites, it’s just a reference.