@Wholesome_Goth Yes, it's safe to delete everyting in DCBackup except ccmerged.package. The other files are duplicates of items you've installed through the launcher, both store and custom content. If you were to create something and export it in Sims3Pack form, and that creation used cc, the DCBackup files would be necessary to make that cc stick to the file. Other than that, they have no use.
Side note: The .package files in DCBackup work the same way .package-based cc does, so if you wanted to convert a Sims3Pack to .package form, you could install it through the launcher, grab the .package files, and dump them in Mods\Packages, then uninstall the cc through the launcher or delete the .dbc files in DCCache. This doesn't work for store content though, since it's encrypted.
If you're wondering about any other files in the user folder, here's a description of what they all are and what's save to delete:
