I see many trans guys on T who still have high voices, but only because of the way that they talk.
Instead of trying to lower your voice while still speaking from your throat (and sounding like Fred Flintstone!), make an effort to speak from your sternum. Put one hand on your chest and one on your throat, start speaking, and feel to make sure most of the vibration is coming from your chest.
I hope I was helpful!
-N
P.S. @palexander is correct — a sample of your voice would be helpful to us for giving you advice, but if you are uncomfortable with that idea, no worries.
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