About 15 minutes each, with rest days between: two days on, one off, two on, two off. Short and regular beats long and rare.
Play a round of Pitch Match after a session or on an off day. It is gentle on the voice.
Chest voice is your speaking register, strong and full. Head voice is the lighter register above it. The passaggio is the few notes between them where the voice wants to crack or flip.
Range grows mostly by smoothing the passaggio, so Session B spends its time there with "nay" and "mum". Never carry chest voice up by force. Let it thin out and mix.
The timbre snapshot gives rough numbers from your phone's microphone. Compare yourself week to week on the same phone. They are not a studio measurement.
With the microphone on, the tuner shows whether you are too high, too low or on key, and scores each scale. Use headphones so the microphone hears you and not the piano.
After each scale you rate the hardest notes. "Easy" takes it one semitone further next time, "Strained" pulls it back.
No sound? Raise the media volume. Headphones give the fairest pitch scores.