Kinda agree with you Noah, IMHO you can have both or either one...
I would think generally that Gender Identity Dysphoria is about how you behave or how your natural instincts lie, it can lay dormant for many years of course too. A lot of us have also a hatred for certain parts of our body, this also happens with CIS as well, but for us its most definitely to do with our Dysphoria.
How we develop is governed by our genes, chromosomes etc., often it's congenial which also governs the rate of change etc..., the more your body changes the more you hate it, I would think, certainly from my case anyway. The more my body changed to my birth physical gender the more I hated it, the worse my Dysphoric episodes got, one fuelling the other... because when I was born (long time ago), I had to conform or be committed to an institution!
So I started, very late in life to start changing myself to how I always wanted to see myself, I like it! But being as nature is, we always see the faults or hints of the old you! and I still hate that!
So I don't fully subscribe to the "there're Separate"!
L Katy