Installing macOS Ventura on my laptop

Apple installers are signed and checked for damage before they are allowed to run. When that fails, you won't see a clear message stating that the signature check failed for security reasons. If something interferes with the communication back to Apple while validating a signature it will show "This copy of the Install macOS Ventura application is damaged, and can‘t be used to install macOS."

I see this on managed Macs, corporate networks, and some hotels even. Communications with some Apple services may be blocked. Either a network firewall, VPN, or local firewall on the Mac is blocking access to some servers in Apple's data center that are required.

If you own your Mac and it's not managed by an employer then you should try a different network. Find a local public Wi-Fi and try to run the installer again. Or possibly connect to a mobile hotspot. The installer download is complete so you won't use much data on your data plan as a quick test.

First be sure it is not shown in your application directory and if it is then delete. Then do the download and install again.