On the practical side there are many good options. Using the voice effectively is a key skill in many professions, such as singing, public speaking, education, religious, management. So there are many practitioners, and lots of learning materials out there. So I recommend to check of there are any of those angles that resonate more with you. But very important - this is a challenge that needs practice to overcome - it cannot be dealt with only theoretically! So as a simple starting point is: go on YouTube and search for vocal exercises. Start with something like warmup routines. And then try something like saying the same sentence at 7 different loudness levels, from a whisper into someones ear to a SHOUT that needs to go to another person at the other side of a lake. Observe just how much power you got! This will be awkward and that is good - it means that you are stretching yourself, both physically and mentally! Like at the gym.

Then out a few sentences in the level you feel most comfortable with, plus 1 or 2 steps above. Try whole paragraphs.

PS: drink water and do not push harder if you feel pain.