Dear Team,
Please ignore the post as now I am able to open the designer with the below steps posted on the forum- (Guide to Download and Install webMethods Service Designer Free Download - #2 by opastukhov)
macOS
- Open the downloaded Service Designer dmg file and drag the ‘wMServiceDesigner’ folder to the Application folder.
- Run the wMServiceDesigner/setup.sh file.
- Go to the application Launchpad and run ServiceDesigner to launch webMethods Service Designer.