Google Chrome and other browsers sometimes rename files or struggle with very large downloads (some Realme firmware files are over 3GB or 4GB).
If the download was interrupted, the "central directory" (metadata at the end of the ZIP) might be missing. Download a fresh copy from the Official Realme Firmware site Check File Integrity: cannot find central directory realme flash tool full
If the OFP is valid but the tool fails, extract the payload: Google Chrome and other browsers sometimes rename files
When the Realme Flash Tool throws the error "cannot find central directory," it is telling you: " it is telling you: