I have created a demo of SPFx Webpart With Angular Elements with reference to this link.
I have successfully bundle that project and serve that project with "npm run bundle" and "gulp serve" commands.
It is running correctly in workbench / local. Please refer to below screenshot,
When I have published that solution using "gulp bundle --ship" and "gulp package-solution --ship" commands. .sppkg file has been generated successfully. But when I add that app to my SharePoint page it throws a below error,
If anyone has an idea for the same. Please let me know.
Thanks in Advance.