Process Plan flow with Angular

Using Angular 12 above, I need a prototype of a simple flow chat editor created with Angular, in which after users finish creating the flow chart they could export the value and key to an excel file. you can use Devexpress tools.
see link

https://js.devexpress.com/Demos/WidgetsGallery/Demo/Diagram/WebAPIService/Angular/Light/
https://codesandbox.io/s/overview-devextreme-diagram-forked-s2cye?file=/src/app/diagram-flow/diagram-flow.json