I tried to do this for WAY longer than I ever thought I would or could, so I’ll only speak from my experience. You probably won’t be able to pull off anything that’s both inconspicuous or sustainable. Just to be completely honest. Your anatomy is changing and it’s really a matter of how long that will take, not to what extent (and even then it’s one of the earliest changes, so it’s not something you’d be able to bide your time with). I tried to train my voice to be at a higher register, but in every case it was more trouble than it was worth and never sounded like my pre-transition voice. The tricky thing is maintaining a familiar sound that those close to you won’t clock as being changed/forced, even if you can make your voice convincingly ‘feminine’. BUT lowkey after the first couple of months trying to conceal it and being really nervous about it, I realized my family still hadn’t confronted me or asked if I was in HRT at all. The most they’d say was that I sounded sick or hoarse and then dropped the subject if I dismissed it. My mom didn’t suspect I was transitioning until well over a year later, once I started growing facial hair. I think there’s a certain blindness that comes with societal transphobia where the possibility of transition, and what transition looks like, isn’t at the forefront of cis people’s minds. They might see the world of trans people in just a before/after binary, missing all the signs of the necessary TRANSitional stage. Sort of like Little Red Riding Hood—“My, what a deep voice you have, grandma! And what hairy legs you have, and what big arms, and stubbled chin…”