As a freelance vocal educator, I’d focus more on developing the voice you already have rather than trying to force it higher or lower. Gentle humming, lip trills, sirens and vowel exercises can help you experiment with resonance and control while staying within a comfortable range.
I’d also record the same short exercise every couple of weeks sometimes the improvement is much easier to notice when you compare recordings rather than judging the voice day to day.
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One challenge is practicing consistently when you’re worried about disturbing people around you. This guide has some useful ideas for keeping vocal practice quieter at home while still working through normal exercises: https://tilcare.com/how-to-practice-vocals-quietly-without-straining-your-voice/
I’d also record the same short exercise every couple of weeks sometimes the improvement is much easier to notice when you compare recordings rather than judging the voice day to day.