Let’s just have a look at “The Fear”, if any, of singing, and consider the idea of putting it on the ground.
Then The Natural Minor (Aeolian Mode) 1; 2; flat 3; 4; 5; flat 6; flat 7; 8.
And then have a look at the vocal round in “People Want to Sing”, by Brisbane Band ‘Kooii’. And Try some exercises with Vibrato.
(With Thanks to Peter Hunt and Kooii)