that error means the file you downloaded is the Linux version (the .tar.gz with a bin/NeoForge inside), and macOS can’t run Linux programs. For your M5 Pro, grab the macOS Apple Silicon .dmg instead, open it and drag NeoForge.app to Applications. Since it isn’t signed by Apple, the first time macOS will block it: go to System Settings → Privacy & Security and click “Open Anyway”. You can delete the /Applications/NeoForge folder you have now.