Makipu wrote "Is it true that when MTFs take E, it doesn't do ANYTHING for the original voice? "
Sadly when MtF take "E" it does nothing!
The reason is (especially for us older gals) that the voice box is already formed post puberty, and larger than cis females so the resonance is deeper, and the vocal chords are longer creating the lower pitch men have.
No, I'm not a speech therapist, but I've talked to a few and this was their answer. Estrogen does nothing to correct this, just like our feet the bones are formed and the size won't change significantly even as the musculature recedes a little due to hormones. Some things we are stuck with, but there are ways to compensate (like don't wear long toed pumps if your feet are already size gazillion

, and like me I'm daily working on controlling my voice, enunciating more like a female, trying not to slur my words, and working on avoiding a monotone speech.
So I'm sure that if you continue to work on your voice you'll become comfortable with how you sound.
Also remember that if I am correct when starting HRT one goes thru a little bit of puberty regardless of age. Even if you've already experienced it, you get to experience it again when starting HRT.
I'm 66, and have experienced a lot of what a young woman experiences going thru her puberty ( bumping into things with my chest I'm talking about....

So if you are like me in the sense that you desire to be who you feel you really are then you will find a way