MacOS 10.15.7 was the final update for the Catalina generation. It was a stability release that fixed numerous bugs. Because it is the "end of the line" for that OS version, it is the most stable platform for running software on older Macs that cannot upgrade to Big Sur, Monterey, or Ventura.
This is a common error on macOS Catalina. It usually happens when a file is partially downloaded or the security attributes are flagged incorrectly. Download Chrome For Mac 10.15.7
If you’re running on your Mac, you can still download and install the latest compatible version of Google Chrome. While Apple has moved on to newer macOS versions, Catalina remains a stable, widely-used system, and Google continues to support it with security updates and essential browser features. MacOS 10