So if I am understanding this correctly, you are wanting to make it so the dropdown is used in a form and doesn't contain the "All" value? For the latter, in the dropdown's Items property put:
Filter(
colDropDownOptions,
Result <> "All"
)
To use that dropdown in a form, as @Drrickryp said earlier:
Make sure that the Update property of the card containing the dropdown reflects the change. It should be something like Dropdown1.Selected.Value for that property.
The Update property is on the top level of the card (as opposed to on the dropdown itself or another object in the card).
To his point about having a separate list to control the inputs, this is great advice if you are able to do so. Things may work fine until you have a new type of item that a user needs to add that you maybe hadn't considered.
If you aren't able to add a SharePoint list due to permission restrictions or something like that, you could try controlling it by allowing users to add a type to the collection and hope that another user isn't trying to add the same type of item. This way, they could add the type of item they need, write the data to SharePoint, and the Distinct would pick it up from there as it would then exist in your list.
Doing this might require a bit of explanation so I will give you one high level approach. What I would do in this case would be to put an "Add Type" button (or the Add icon, etc.) near the dropdown. This would be used to trigger a variable that would reveal an invisible box of them to enter text, along with a submit and a cancel button. Rather than explaining all of how to do that, I made a quick app to show the method. If you import this app, you should be able to see how it is done.
I commented out the code to update the list in the OnSubmit property of the Submit button, just so you know. Also, I commented out some validation on the DisplayMode property so that people can't add item types that are already in the list and hid an error message in there to let them know (the Visible property is commented out on the error message).
Let me know if that gets you going in the right direction! If nothing else, maybe the attached app has something useful for a future scenario.
