You can customize Opera pretty easily try new themes, rearrange the sidebar, or set your favorite sites as your start page by adding extensions like ad blockers, VPNs, or productivity tools can really make it fit your style.

Ah, I totally understand your frustration. But honestly saying, if sync was turned off before you reinstalled Windows, Opera wouldn’t have saved any of your data to the cloud. That means once the local files were wiped during the reinstall, your bookmarks and settings are most likely gone.