This might have to do with the security settings that prevent applications from unidentified developers or those that are not downloaded by the Appstore.
But there is a fix for that:
1. Press control when opening Bitcoin Core
2. Select open from the context menu
3. Click open once again when the dialog window pops up.
On this way Bitcoin Core will be added as an exception. From now an it should work like an registered/identified app.
Source:
https://support.apple.com/guide/mac-help/mh40616/macI don't think getting the binaries notarized with Windows and Mac certificates (Linux does not use such a feature) for their respective builds should be expensive to obtain though - should only be a few dozen dollars for a certificate. Are you guys aware of anyone in the Bitcoin Core project who might be interested in covering those expenses?