I have experience natural softening of my voice that I attribute to the HRT meds that I am taking.
Maybe it is all in my head, but that okay I like the results. I sound much more feminine naturally.

I don't recall it having had any effect whatsoever on my voice.   In fact, the peeps on the other side of the phone when I would call somewhere or when I was at a drive-thru were responding differently even before I had started HRT.  That was 20'ish years ago...

My voice remained very feminine as it did not really drop any during the first puberty, people have always thought I was a girl especially over the phone.  HRT is supposed to thin out the chords so they can resonate at a higher range of freqs so you can reach a higher voice frequency. but in FTMs it will make the voice deeper. My voice was spared at the first puberty what a nightmare that one was.

I've been getting called "ma'am" over the phone for a long time so I couldn't say.  My first thought is "probably not" since T actually breaks your voice to cause it to get deeper during puberty.  I was luckily spared the vast majority of that damage and have a good voice without much effort.

over the months, HRT has removed most of my voice's deepness. It went from sounding like a 40 years old man (I was 17 at the time) to sounding mostly androgynous (and i'm only 18 now, 10 months into HRT)

I've heard that if you transition early enough, that your masculine vocal features are 'soft' enough to unravel away from masculine developments...I don't know if it's true, though