dude. were you able to develop falsetto after taking t??? cuz that would honestly change things for me. the main reason i've never considered it is cuz i love singing high and losing that would be more devastating than the euphoria singing low would give me. but if i could get falsetto... damn. that would be the dream. just wanna be a boy soprano.
*disclaimer I am not an expert!*
Gunna put on the Music Nerd Hat here - SO THE THING ACTUALLY IS is that Falsetto is Not Different At All from Head Voice and If You Practice You Can Keep It!
I used to sing classically quite a bit in high school/college and was always an Alto With Good Range (aka could've been a high reaching S2 but due to lack of numbers was delegated A2 because I could hit the low notes comfortably and reliably) and one of the things I was MOST proud of was that I had a VERY smooth flip from chest to head voice. So, even though I wasn't competing anymore like I used to when I started hrt, I was still pretty nervous about "losing my range" and losing that smooth flip.
But the thing I learned from my vocal coach and my brother who has a masters degree in this sort of thing is that you don't really "lose" the upper register when your voice drops, it's just that it shifts.
I don't know the like exact science behind it - I can really only tell you what it feels like personally/vague recollection of high school biology class - but testosterone thickens the vocal chords, thus producing a deeper tone. So think like a guitar string - you have the thicker string and a thinner string and while it's easier to produce a higher note with the thinner string, you still can get a high note with that thicker string. The difference between your voice and a guitar string is that testosterone is not an instant effect so you don't like. Go to bed one night and wake up the next morning with a different voice, no matter how much it actually feels like you do. ALSO!! How MUCH testosterone you put in your body affects how much your voice changes!
My personal experience was that I was SO EXCITED about my new voice and seeing how low I could go, I forgot for a while to keep up my exercises for my high register. And when I did remember, I found that the muscle memory was.... different? I'll say different. This is already getting long so if you want I can go into it a little more later but mostly the important thing is that we just call Falsetto and Head Voice by two different names despite the fact that they're really just the same thing. You might find that it's not as smooth a flip as it used to be naturally but if you keep up your exercises/use your high register it will continue to work. You might find you lose like. A liiiiittle bit off the top (probably won't be doing any more Phantom of the Opera Shrieks) but Jeremy Jordan's Song Book won't be a problem
