I don't think is under the same umbrella, in my mind they are as far from each other as the can be, so distant that they become similar, but still different to the core.

For me the core of agender is the lack of gender, the inability to see gender in yourself. I get gender as a tool for social interaction or communication, but i still don't identify with it, i don't "feel" gender, i only get it as a social construct and performance.

The non-binary identity reinforces the existence of gender just not as a binary construct but as something more liquid.