Help with dropdown that shows data from a collection

Hello all. I’ve been using Directus 11 for about a week now and it’s been great, but there are some limitations for which I’m hoping to find workarounds.. The biggest one is the Dropdown field and its inability to pull from a collection (or inversely, the inability of an M2O field to display as a dropdown..)

Basically, I have a categories field that contains nested categories. I would like to set up a dropdown to show just the leaf data - basically any category which does not have any more children.

So if there are the following categories:

Electronics
Furniture → Seating → Chairs
Appliances

The following will be shown in the dropdown:

Electronics
Chairs
Appliances

I’ve tried so many different things and I just cannot find a good solution. Any direction would be fantastic. Thank you and HNY!