If not, try typing the following command line in the terminal to turn off the Gatekeeper feature.
Then, select' Anywhere' in the 'Allow apps download from:' option.
Meanwhile, if you have previously installed Bitcoin Core and want to install the latest version without deleting or overwriting the old version, try changing the name of the previous Bitcoin Core app first. I implemented it on macOS by renaming the Bitcoin Core App and adding a version number to differentiate it.