Apparently a co-worker accidentally overwrote a static resource zip file. I do weekly backups. Is it possible to retrieve past static resources from a zip file?
The Weekly/Monthly Data Export function does not back up metadata configuration files. For metadata, you should be using a source code repository (e.g. Git). This allows you to recover changes to your fields, objects, classes, static resources, and anything else you want to back up configuration-wise. You can even use SFDX to make it easier to migrate changes between orgs.