Yes labels are weird. However I can't relate to the idea that my sexuality isn't changing.
Already transition has radically shifted how I relate to my own orgasms; it's different in ways I'd never expected. My gf has experienced her own changes as I first became far less sexual and internally bordering on asexual. Now, since adding progesterone I'm becoming more assertive on being treated as feminine (she's never much paid attention to my breasts and I find I want that even more now as they've become far more erogenous).
Using my penis (I like to use Julie Vu's moniker sheenis now) has always been an act of passing. And I passed well, with flying colors even though I've been cross dressed for sex exclusively for 20 years now.
I've also used a strapon, sometimes just for play, others to relieve myself from the responsibility of having an erection and to explore what itay be like to use one after GRS. However, after GRS that's going to be the only way for her to get that with me and we both know it's not the same.
We've always had a strong sexuality and I have no desire to see that go away. On the receiving end I'm so excited at the prospect of vaginal sex; anal is fine as far as it goes, the downside of more extensive prep and foreplay we find cuts into spontaneity.
It may well be sometime down the road I will find these changes have all become part of the background and possibly I will feel as the OP expressed, however I don't want that. I can remember so much of my sex life, it's all vivid and I can't imagine I won't remember the differences.