This might be a bit tricky, as usually the items in the dropdown list is either populated from a local list tied to a property (which we don't delegate), or populated from a Data Page that sources from a Data Table or external source. Delegating the Data Page is meaningless and it's not possible to delegate a "Data Table" as well.

I guess an option will be to create a UI to retrieve records from the data source where the reference data is persisted, then allow the user to modify the information from it.You can call this UI through a Local Flow Action (Optional Action) and it is used simply to maintain the list of values.

Anyone else has a better idea?

Create a data table with the options and then delegate the data table.

You can delegate a Data Table by Actions->Delegate 

Thanks DipakR15 and CHUAT, will try these approaches and share any learning in some time.

We can delegate a data table. Use that table data to populate the data page & use it to display the available options.