Hey! I have dealt with the same issues with lighting concerns. I am brand new to all of this, so I'm definitely not an expert, but here is what I do:
First of all, I am a high school English teacher in the Mississippi Delta, so I don't bring in a lot of cash anyway since teachers are paid so little (which is especially low in Mississippi, and even worse in the Delta). Therefore, I am not in a place where I can sink a bunch of money into creating my YouTube videos. I started posting videos as a hobby, but just like everyone else, I am hoping to make a little side cash just to help make ends meet. Plus, as we have all discovered, it is such a fun thing to do!
My point is though, I don't have some big expensive camera or big nice lighting set ups or anything of that nature. When I posted my first few videos, I didn't like the lighting, just like the issue you say that you are encountering. I did a lot of trial and error, and my lighting is still by no means perfect, but I have improved it quite a bit by:
When I make a product review, I sit against a wall in a room where I can have a window in front of me behind the camera. I open the blinds all the way so that I have plenty of FREE
natural light coming in. If the light from the window isn't enough due to weather or time of day, I open my laptop behind the camera and pull up a white screen and adjust the lighting on the laptop to a higher setting. This way gives me more light shining directly at my face. Now when I create a video of my Cockatoo, Maui Lynn, (which the majority of my videos are about her) the lighting problem seems to be harder to solve. Most of the things she does that I have recorded are spontaneous actions and situations that she does when she feels like it, lol. Anyway though, that's what I do that seems to work ok for me
I hope that helps you a little!