Are zip files vulnerable to corruption?
Yes, which is why a good backup schema verifies the newly created backup file matches the content of the source file, and also that multiple copies to different media are made, each verified.
Good backup includes verification and redundancy. That's why most backup schema recommend multiple copies, with at least one copy offsite, whether in the cloud or physically transported offsite. That resolves the small chance of bit rot.
The 7-Zip Open Source package, one of the many programs which can make and open ZIP files, includes recovery instructions, but their language regarding your chance of recovery, you will notice, is guarded.
Your chance of recovery also depends on where the corruption is; if it's in the dictionary, everything in the ZIP file is toast, which is why modern ZIP files have two copies of that dictionary.
ZIP and 7Z files should not be used to back up Linux and UNIX files, as (unlike Windows) the ownership and group data for each individual file stored within the ZIP and 7Z archive is not preserved if the ZIP file is created from Linux or UNIX. That's why Linux and UNIX backups archive first to a TAR file to preserve that data, then compress the TAR file.