XLD can't come past the Gatekeeper anymore, so I wonder what other macOS users use nowadays to convert .cue-sheeted CD images into single WavPack files. FFMPEG could probably work, but I'd rather have a two-button solution... 🙂
Why don't you just disable gatekeeper?
That's one of the FIRST THINGS I do when I set up a new Mac.
Open terminal and enter this:
sudo spctl --master-disable
(password will be required)
Then, open the Privacy & Security settings pane, scroll down, and set the "Allow applications from" popup to "anywhere".
Again, password may be required.
That's it, you're done.
See if the app you want to run, runs now...