I use Entity Framework Core 2.2. It does me a solid by constructing the entire hierarchy from the database without me asking it to. That said, your TreeList actually binds to a Flat structure. Your model definition then defines how the hierarchy is built.
Do you have an example of how you use EF with your TreeList? Do you have tools or a method that I could use to convert what I get from EF over to what your control needs?
I have a self-referencing Group table:
ParentId references Id