Feature Request: [AutoCompleteTextField/Picker hybrid] Control combining manual input with prepopulated lists

[StepKie]

The functionality I am often searching for lies somewhere between PickerField and AutoCompleteText field.

The user story is basically I want to enter something in a field, and if it is not in the supplied list I want to freely enter my own value.

The PickerField makes browsing the existing choices convenient (at least if they are limited to not more than about a dozen), but I have no ability to enter my own value if I am unhappy with the choices provided.

The AutoCompleteTextField comes closer, but here the issue is I might not know what I am looking for initially (exact wording/spelling etc.), so I can only materialize choices by typing, but I can not easily inspect the range of choices beforehand.

I hope this description makes sense?

we currently use a custom built control like this

where you can type manually, or click the chevron to get offered a list of choices on a separate page.
The user experience is however slightly suboptimal there (a lot of manual management and navigation). It would be nice if there was a standard control for this where I could provide an ItemSource for the default choices (like for AutoCompleteTextField), but there was an easy ability to bring up these default choices at a glance (not possible in AutoCompleteTextField).

Hope this makes sense.
Best regards!