I meet the same problem, can someone help with it pls?
If you encounter OP problems in exactly the same way, do the following.
So make sure you unmount any currently mounted Bitcoin Core installation drive, to make sure you did not mistake it with the older version, then click the dmg and check the mounted drive.
Try to check the Bitcoin-Core mounted drive on the "Locations" sidebar of Finder.
This might have to do with the security settings that prevent applications from unidentified developers or those that are not downloaded by the Appstore.
OP problem has nothing to do with binary notarization. It is a different matter.
Are you guys aware of anyone in the Bitcoin Core project who might be interested in covering those expenses?
The notarization has already been talked about. But it's hardly about money problems. See
https://github.com/bitcoin/bitcoin/issues/15774.